Trapped Inside an Iceberg
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It's morning on February 17th, 2001 at the bottom of the Southern Ocean. A place of extreme darkness, quiet and cold. The glacial water here is a brutal -2 degrees Celsius. Rising up from the seabed is a colossal white mountain. A giant iceberg, hundreds of feet tall. A glassy frozen monster in the sea off the Antarctic coast. It may appear solid, impenetrable.

but there are cracks and crevasses scarring its surface, openings which lead to a labyrinth of caves and passageways within. Nobody has ever explored inside an iceberg before. That is, until now. Swimming through this claustrophobic sub-aquatic world is 37-year-old Jill Hyneth. With care and expertise, she swerves her way through frozen underwater tunnels, her spotlight glistening off the icy surfaces.

Alongside her is her husband and longtime diving partner Paul. Together, they're history makers. At times, they're navigating passageways so small that their diving gear scrapes along the walls. Little bubbles dance their way out of thin cracks all around them.

The air was being released from the ice and fizzing and cracking and popping. And I could hear sounds like that, but I could also hear at times the deep groaning. And I knew that was the ice. I'd heard it before swimming underneath ice, but never from being inside the ice. The foreboding groans and rumbles continue. A tense soundtrack accompanying their exploration.

And then, Jill notices something far more concerning. The water starts to spin and tug at her. Inside the iceberg, the currents are suddenly changing.

It's incredibly difficult to predict what the current might do on any dive, but it's impossible down in a place like Antarctica. You're dealing with freshwater melting ice into a saltwater environment. Two different densities of water. One sinks, one floats. And that causes currents that you can't predict either. Vertical currents that can flush you down into the depths or can rush into an environment like a tunnel inside an iceberg.

I realized the current was too strong to swim against. And I looked to Paul and he looked to me and we went, "Oh boy, what do we do?"

In this episode, we meet Canadian diver and underwater filmmaker, Jill Hynath.

Jill is a pioneer forging a distinguished career in a male-dominated and highly dangerous profession: cave diving. In 2001, seeking to achieve a world first, she travels to the South Pole. Here, she encounters some of the most punishing conditions on Earth. We're working in water that's, you know, minus 2 C. One tenth of a degree colder and it would be frozen solid. It doesn't get any colder and still be liquid.

It's the most audacious and perilous of missions. And when an underwater cave threatens to trap Jill forever, every breath becomes precious, and every decision becomes life or death. If I have an air supply failure, if I have some problem with my equipment, I have to deal with it in place. There's no mission control to call for help. I'm John Hopkins. From Noisa, this is Real Survival Stories. It's late January 2001, somewhere in the middle of the Southern Ocean.

A small research vessel, the Braveheart, is tossed about on the 60-foot swell. The little 118-foot boat pitches over another gigantic wave, her bow breaking through the surf. Below deck, Jill Hyneth clutches a handrail, staring out of a porthole at the dark, heaving mass of water. Her face is gray, her knuckles white. Her arms and legs are bruised from repeated collisions with bulkheads and watertight doors. Jill is on her way to the bathroom.

She's struggling to keep her lunch down. We had to travel across the Southern Ocean for 12 days. I never envisioned how bad it would be. I hadn't been seasick in my entire life, but from night one, I, like everyone else on the boat, were being violently ill. And I thought, wow, what am I in for? The Braveheart is traveling south from New Zealand.

Providing the crew survives the crossing to Antarctica, a potentially enormous prize awaits. Jill is risking her reputation, maybe her whole career, on this outlandish adventure. It all started a year ago. I was working full-time as an underwater explorer, filmmaker, photographer. And with my colleague, Wes Skiles, we decided that we wanted to go to Antarctica.

And we started putting together this story about how we would sail from New Zealand down to the Ross Sea. And then something extraordinary happened. The largest iceberg in recorded history calved away from the Ross Ice Shelf in Antarctica. The iceberg, labeled B-15, is the largest moving object on Earth at 4,500 square miles.

It's the same size as Jamaica. Jill wants to explore B-15 in order to test a bold hypothesis. She believes icebergs should contain cave systems similar to those found in sedimentary rock. Twelve months ago, she took the idea to National Geographic. An ice cube isn't this solid mass of ice. It's full of little cracks and holes and pores. I kept thinking, you know, what if you could swim inside these cracks and crevices?

And so as we watched this thing break away and we recognized the scope of what this was, we thought this is an extraordinary moment, a moment in time on the planet. And what might this mean in terms of climate change and sea level rise, something that people were barely talking about back then?

And that's when we went into a meeting with National Geographic and said, hey, we're going to go down there. We're going to be the first people not just to intercept this iceberg, this massive piece of ice, but we are going to be the first people to ever cave dive inside an iceberg. They left the meeting with a large check and permission to put together an expedition to the Southern Ocean.

Aside from leading the dive team, Jill will also co-produce a documentary of their voyage alongside her colleague Wes. But the truth is, it is all a massive gamble. Jill's theory about ice caves is just that, a theory. She has no evidence, no books, no maps. No one has. But that's also the allure of it. As a child of the 60s, inspired by grainy images of people walking on the moon, Jill always dreamed of being an explorer.

But rather than going into space, fate led her underwater. It turns out they're not worlds apart. Although I wanted to be an astronaut, I kind of ended up doing a lot of similar things. It's me being an extension of scientists' eyes and hands in environments that they cannot get to. And although people call cave diving a sport, I don't think of it that way anymore.

For me, you know, it's swimming through the veins of Mother Earth, exploring places that nobody's ever been to. Diving is extremely dangerous, and so is caving. Jill does both at the same time, venturing deep into underwater tunnels with no direct route back to the surface. Accidents tend to be fatal.

I've lost well over 100 friends to cave and technical diving accidents. And that's really sobering. It makes you reflect upon risk and how that risk can spill messily on to others, your community, your family, your friends. But I don't do these dangerous things regularly.

dangerously if I can. I mean, I try to mitigate risk. I try to think of all the things that can kill me on any given day before I take on a risk and try to ensure that I'm entering the water with the safest possible mindset, with the best possible equipment and the right people around me. But this expedition will be more dangerous than anything she's attempted before. They're two and a half thousand miles from the nearest hospital with no Coast Guard support and no quick routes back.

I mean, you're going to the far corners of the planet, taking huge risks. But in our case, we didn't even really know whether we would find diveable caves. It was a hypothesis. And the pressure of bringing back the goods for a National Geographic story, for a movie, are huge. I mean, that's a lot to take on, a lot for a young person to juggle. At least she's in good company. On board is a well-drilled team of 18.

Various technicians, researchers and scientists, plus fellow divers Wes and Paul, Jill's husband. Both are older and hugely experienced, but they'll be looking to her as their leader. Both of these guys are incredibly talented cave divers with a wealth of background, but neither were cold water divers.

And so I had planned to train both Paul and Wes in diving in ice environments. And originally we had planned to come up to Canada and do the training and spend some time. But as happens when you're planning an expedition and time gets short, we got closer and closer to departure and we kind of ran out of time. It isn't ideal, particularly for someone as methodical as Jill.

But Paul and Wes will just have to learn on the job. After 11 days at sea, they're approaching 66 degrees south, finally crossing into the Antarctic Circle. Staring at the vast, endless waves before her, Jill feels another bout of nausea and lurches towards the bathroom.

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Call 800-333-4KIA for details. Always drive safely. Limited inventory available. Warranties include 10-year 100,000-mile powertrain and 5-year 60,000-mile basic. Warranties are limited. See retailer for details. It's midday on January 29, 2001. The storms have lessened, but the cold is growing. Moving further south, the Braveheart's pace is reduced to a crawl as it navigates the dense sea ice. Snow swirls around the deck.

Tethered to railings, clad in thick parkas, Jill and the crew attempt to de-ice the ship's hull and railings with hammers and crowbars. They're behind schedule, rapidly burning through fuel and food supplies, and the ice is only getting thicker.

I recall hearing it scraping along the hull. It's just this loud ripping sound. And then finally, you know, got to the point the ice moved in, froze solid, and we had our Shackleton moment, which was, all right, we're shutting down.

We've got to preserve the fuel. You know, we need to conserve. So we turned down the thermostat in the boat. We turned off the engines and waited it out. For two days, they're trapped in the ice. The crew watches helpless as the seasons change before their eyes. Every day the sun gets a little lower and darkness starts encroaching. The summer is ending, which means colder temperatures and more ice.

Already, their mission is in jeopardy. Luckily, on the third day, the pack shifts enough for them to break free. But it's clear they're not going to get all the way to B-15 as they had originally hoped. Instead, they agree to get as close as possible and try to locate one of the mammoth chunks that have already broken off from the main iceberg. In the meantime, they'll conduct their first practice dives. It's time for Wes and Paul to experience the realities of cold water exploration.

The three of them go out in a small inflatable skiff known as a Zodiac. Along with specialized breathing equipment and diving kit, they've also got lights and filming gear they need to test. In particular, Wes has a brand new 80-pound HD camera they have nicknamed "The Beast." He's keen to try it out underwater.

Paul and I were already in the water. The moment that he rolled into the water, he flooded his dry suit in minus two Celsius water. So he gets this complete rush of cold water into his suit. And then he said, I'm just going to get a minute of footage so I can look at it in the camera. And before I had even said, yeah, because I wasn't going to say, yeah, he descended.

Before Jill can stop him, Wes goes under. It's a serious, potentially fatal error. Less than a minute later, he resurfaces, frantically signaling that he needs to get out. He tries to pass up the camera, and that's when I realize that, like, he's physically weak, and he looks really bad. And I'm like, we've got to get him on the boat.

And then once he's in that Zodiac, we had to rush him back to the main boat. And he was already suffering from extreme hypothermia. We got him into his bunk and piled him up with blankets and sleeping bags. But he was shaking uncontrollably and really looked bad for quite a while. It was a scary, scary experience. And after that, he wasn't eager to get back in the water again. Minute one of dive one, and it nearly ends in disaster.

It's a sobering warning of things to come. It's February the 14th. Nearly a month after departing from New Zealand, the crew of the Braveheart finally arrives at their destination, or as close as they're going to get. Now they only have about a week before they need to turn back, or they'll be trapped over winter. Dropping anchor and making camp, the crew scans the area, and then they see it. A floating, flat-topped mountain of ice looming two or three hundred feet up into the sky. It's just what they've been looking for.

an immense breakaway piece of B-15, reachable from their position by skiff. Leaping into the zodiac, Jill, Wes, and Paul are taken out by first mate Matt. As they approach the iceberg, they see it as a feature that looks especially promising, a large crevasse carved into its side.

I knew that the bulk of icebergs is actually beneath the surface and you only see a little bit of it topside. So as we approach this large chunk of ice, I was seeing this very sheer cliff a couple hundred feet high with a flat top and I thought, ah, this is it. You can also see perpendicular cracks that go into the ice and you see these deep blue hues and darkness extending into the ice.

And I thought, all right, that's where we should start. Let's dive into one of these crevasses and see if it does extend downward. This is it. Jill's chance to validate her theory. She and Paul get ready, double checking their wetsuits, air tanks, lights and cameras. The divers give each other a nod before rolling backwards through slushy floating ice and into the coldest water on Earth.

You get this like slamming headache from that cold water hitting your bare skin of your face. And Paul rolls into the water too. And we look to each other and gave a thumbs down signal to drop down through this slush.

Suddenly, I was in clear, deep water with just that slush and chunks of ice above my head. And the sunlight would filter down, illuminating this crevasse that descended out of sight into the blackness. The fissure seems to continue down the entire length of the iceberg. They slip inside and start descending into the void, a shadowy abyss of unknown depth.

And as I looked to my left and my right, I could see the texture of the walls that appeared like the texture on the outside of a golf ball, like little divots that were obviously carved by the current of the water, carved by the hand of the sea. And I was like, oh, my God.

And I reached out and sort of touched the wall to feel these smooth surfaces and realized that there were stripes of layers of ice, some that were white, some that were clear, some almost transparent, like glass. And then a surprise. It turns out Jill and Paul aren't the only lifeforms here. As she touches the walls of the crevasse,

Tiny, transparent fish come scuttling out of the small holes, zipping around Jill's gloved hand. And I thought, well, isn't that fascinating? I mean, they camouflage so well with the ice. How on earth do they survive in water that's this cold? As Jill and Paul drop down further, the distant daylight grows dimmer, and they switch on their cave lights. At over 100 feet down, they're approaching their maximum safe depth.

And we got deeper and deeper and I started to make out what appeared to be seafloor beneath me. And I wasn't expecting that because I shouldn't be reaching the seafloor so quickly. It was about 130 feet deep and there it was. This iceberg had been sort of stuck on the seafloor as it moved through the ocean.

And we got down there, and when we did, I looked to my right, and I saw this arched tunnel, you know, proceeding beneath the iceberg. It was a spot where I could go underneath. It's the opening to an underwater ice cave, just as Jill had predicted. Hearts pounding with excitement, the two divers assess their surroundings before carefully swimming inside the opening, vanishing into the blackness.

Inside, they scan around with their lights, illuminating a series of blue and white chambers and passageways. They've discovered a vast cave system inside the iceberg. A frozen warren of caverns and curves and craters, suspended over the Antarctic seabed. And that's not all. The ocean floor beneath them is awash with life. Across the silty bed is a thick carpet of grass and plankton.

Throughout, they see sponges, anemones, and even crawling sea creatures, isopods, and spiral worms that seem to glow with phosphorescence. It's all beyond Jill's wildest dreams. It was something I had never expected.

And it was at that moment I turned to Paul and I must have let out this huge, you know, "Woo!" I was so excited because I knew that we finally had, you know, a cave that I thought fulfilled the vision of what we were promising to National Geographic and more. The minutes passed by quickly as Jill and Paul enthusiastically filmed their remarkable surroundings.

Occasionally, they hear strange, almost otherworldly sounds echoing around them. We shot a bunch of footage inside this tunnel, but while we were filming, I was listening to these sounds, these cracking, these groaning, these, you know, sounds that were deep and loud enough that I was actually feeling them in my body. The iceberg rumbles as they continue to explore.

But being down at maximum depth will mean some lengthy stops on the way back up. In order to fully decompress, their time is running short. Reluctantly, Jill gives the signal to head back to the surface. Paul acknowledges, and together they begin their return journey. They carefully navigate back the way they came. But when they eventually reach the entrance to the caves, Jill realizes something has changed. As we swam up, things didn't look the same.

And I thought, uh-oh. I realized that the very opening that we had swam into was gone. Those rumbling sounds they heard make sense now. Around them, the ice has cracked, shifted, and altered. And now there are huge blocks barricading their way out of the iceberg, utterly terrifying. But Jill is experienced and remains as calm as possible.

Together, she and Paul start pushing and probing their way through the frozen debris at the mouth of the cave. It's tough when this deep and this cold, but slowly, air claw their way through the icy blockade. When they eventually resurface into the frosty air, they are met by the Zodiac. Wes and Matt are beyond relieved to see them.

And I remember the look on Wes's face. Like, it was like, wow, we thought you were dead, was the first thing that he yelled out.

So Topside, Wes, and our first inmate inside the Zodiac had experienced a calving event. Literally, this sheer face of ice had cracked and slid away, causing this massive wave that almost dumped them out of the Zodiac and had sealed the entrance that Paul and I had gone into. It terrified them. He was convinced we were gone.

Back on the Braveheart, the mood is a mixture of triumph and contemplation. The iceberg is manifestly hazardous and unstable, but on the other hand, they did it. They have proved the existence of ice caves. What's more, they have discovered a whole ecosystem of underwater life thriving there. Despite the dangers, there's no way they're going home just yet. It's the morning of February the 17th. Back inside the iceberg, Jill flicks her flippers and glides deeper into the caves.

Paul is right beside her. They occasionally swim up to what appear to be open passageways, only to run into sheets of crystal clear ice blocking their way. It'd be all too easy to get lost down here, so they're taking precautions, using ice screws to lay guidelines, allowing them to retrace their way back. There are some dangers you can never plan for. Jill suddenly feels the currents shift.

It's incredibly difficult to predict what the current might do on any dive, but it's impossible down in a place like Antarctica. You're dealing with freshwater melting ice into a saltwater environment, two different densities of water. When Paul and I turned around, I realized the current was too strong to swim against. And I looked to Paul and he looked to me and we went, oh boy, what do we do?

In an instant, the guidelines leading them back to the surface are useless. They simply cannot swim against this current. Again, Jill tries to keep a calm head. Her years of expertise will be crucial now. When, hundreds of feet below the surface, life is measured in breaths.

When something scares you, your heart races, you start to breathe faster, and then your brain erupts into what I call chattering monkeys. There's a million voices in your head. Maybe your life is flashing before your eyes. But cave divers can't do that. We can't afford to waste gas. We can't afford to waste energy. We can't afford to lose focus. The current is pulling them deeper into the iceberg.

Rather than fight it, Jill turns and shines her torch in the direction they're now being forced. Faintly, in the distance, there appears to be a tiny patch of daylight. And where there is daylight, usually, that means there is a route back to the surface. How far away it is, whether the course is clear, or where exactly they'll emerge, they're all problems for later. Right now, it looks like their best bet.

In that moment, we had to make the best possible choice. And I think that that's something that cave divers are really good at. When something scares us, the first thing we do is take a deep kind of cleansing breath. And we decided to sort of roll the dice and head for that exit. Jill bursts through the water, the Antarctic wind suddenly blasting across her face. She turns to see Paul's head also bobbing above the surface. They're out.

But they're also disorientated. Ice sheets encircle them. It's unclear where exactly they've emerged, and there's no sign of either the Zodiac or the Braveheart. When I popped my head above the water, I was able to breathe surface air. But as I spun around 360 degrees, all I could see was ice. I couldn't see the boat. And I realized the boat couldn't see me either.

I had a sense that we could be as far as a mile from the boat. And it was then that something fortuitous happened. I guess the boat had lost its anchor. It was drifting backwards. And as it drifted backwards and, you know, powered up the engine, I could hear that rumbling in the distance.

And then I just saw a tiny, tiny sliver of the boat kind of appear as I looked down the edge of this ice that we had just escaped. And then I heard the most beautiful words I've ever heard in my life. I heard Wes on the back deck going, is that Jill? Jill and Paul are eventually retrieved from the water.

By pure luck, they emerged on the other side of the iceberg, just a few hundred yards from Braveheart. At the very moment, it lost its anchor and drifted towards them. It's another close shave, which Jill and the rest of the crew acknowledge. But just hours later, back on board and reviewing their footage, they can't help but feel they need one more dive to complete the project, in spite of the obvious risks. What Jill doesn't know is that the dangers they've experienced so far

will pale in comparison with what's to come. We still hadn't gotten Wes into the water with the good new HD camera at that point. We'd shot some footage, but I didn't feel like we had the goods. I didn't feel like we had the images for National Geographic yet. I didn't feel like the story was finished. And so we had a really thoughtful meeting, but made the choice to take that risk.

It's the following day, February the 18th. Once again, Jill and Paul weave their way through the iceberg's internal maze. This time Wes is with them. He's a little less graceful in the water than his peers, partly because he's less familiar with the surroundings, but also because of the hefty HD camera clasped in his hands. Today, they have planned for a shorter one-hour dive. With the extra gear, a third diver, and with everything that's already happened, Jill isn't taking any chances.

I could tell Wes was excited. We had actually storyboarded out the shots that we needed. We get down to the seafloor. Let's get some of these animals. We'll go in a little bit. We don't have to go too far, but let's, you know, get what we can near the entrance of this cave. This time, they only swim a short distance into the iceberg. But even this proves harder than expected. Today, the current is fighting them like it's trying to keep them out.

Eventually, they make it inside to a sheltered chamber where they can film. Despite some initial apprehension, it doesn't take long for everyone to relax and appreciate the amazing visuals they're capturing. It was exciting. On that dive, there were these isopods about the size of my hand that are like

giant cockroaches would be the best way to describe them. And there were thousands of these mating pairs of these giant cockroaches crawling over the seafloor, but also falling out of cracks and crevices in the ice on top of us. It was like horror movie kind of stuff, but it was also like, wow, this will be in the story. This is cool. But Jill's reverie is suddenly interrupted. From nowhere, she feels a sharp pain in her left hand.

A burning, throbbing sensation slowly spreading down her wrist. There is a small leak in her glove. She clenches her fist tight and crosses her fingers in an attempt to keep them warm. As ever, it's all about risk versus reward. And at the time I thought, this is my last dive inside an iceberg, so I'm going to put up with this as long as I can.

I had some thermal liners that would, you know, mitigate that cold a little bit, but it was painful. They go on filming a while longer, but it's getting harder for Jill. Her hand is now completely numb, the fingers frozen stiff. So when she notices the faintest nudge of a current now pulling her deeper into the caves, she's in no mood to hang about.

I felt the tide starting to change and the current that we had fought against to go in was now like sucking us into the iceberg. And I thought, oh, this can't be good. And I know we had lots that we still wanted to film. I know we had a shot list left to do, but I turned to Paul and Wes and put my thumb up and I called the dive. There was no argument.

They all turn and head straight for the cave entrance. But without warning, the current strengthens. They kick harder and harder, but it's no use. I was working at the peak of my physical ability, and I had to dig my hand into the doughy seafloor where all this beautiful life was and try and pull myself across the seafloor to get back to the crevasse where we could swim to the surface.

Jill plunges her hands deep into the clay below her, sending up a cloud of dark silt that momentarily blots out their lights. It takes all her strength just to steady herself. She's breathing hard, the sweat pooling inside her drysuit. In spite of her vigilance, in spite of her precautions, in just a few seconds a leisurely dive has become a desperate fight for survival.

And now I'm panting and wheezing and yeah, there's a glove full of water and it's cold, but the rest of my body is like at max output trying to get out of the cave. And I remember thinking, we're not going to make it. We're not going to make it. We're going to get sucked in. Still hanging onto the seabed, Jill swivels to check the guys are close behind. Without radios, they're only able to communicate through distorted vocalizations into their mouthpieces.

What Jill hears next beggars belief. And I turned to Wes and Paul and Wes yelled, help me with the camera. And I remember thinking, F the camera. Like, no way. We're about to lose our lives. Dump the equipment. Like, our lives are more important than the equipment. And then Paul dropped back to help him lug the gear. And I'm like, oh, no.

Jill's colleagues perhaps haven't yet registered the grave danger they're in, but this is now far worse than any previous situation down here. Just the effort to cling to the ocean floor is hugely draining. The current is punishing, and the strain is causing Jill to breathe faster. If she produces too much carbon dioxide too quickly, she could pass out. For a second, her eyes land on a beautiful sea sponge flexing effortlessly in the current. For a brief moment...

I recall thinking, I could die in the most glorious place that nobody has ever seen. It's beautiful here, but this might be my grave. And when those thoughts creep into your head, that's when you have to tamp them down because they can just spiral out of control into panic. Jill curses as Paul drops back to help Wes with the camera. She can't afford to stop.

If she doesn't find them a way out, they're all as good as dead. Steadying her breath, she lunges forward again with both hands, grabbing onto anything she can. Meter by meter, she scrambles and scrapes her way forwards. After what seems like an eternity, she makes it back to the cave entrance. But when she pokes her head out and stares the 130 feet up the crevasse, she is hit by a shocking, monumental force.

A powerful vertical down current smacks her like a freight train. It slams her back, pinning her body to the ground. It was at that point at the cave doorway where the light is actually filtering down from the surface.

where you would think that that would give you a glimmer of hope, but that's where the current was the strongest. There was this unbelievable force just barreling downward, and every time that I tried to get up off the seafloor and onto that ice wall, it would just push me back down again. Jill stares up the sheer ice wall, mottled and carved by the currents. She can see the distant lights shimmering on the surface far above, and then...

Out of nowhere comes a moment of inspiration. And that's when I remembered something that I had seen on earlier dives. There were these little ice fish about the size of my thumb that were actually burrowing little holes in the ice about the size of my thumb.

So I got myself back to the point where I was at the wall and I realized I could stick my fingers into these holes and try and lift myself up a little bit, finger by finger, like rock climbing up the ice face. Forgetting the pain in her hand, she digs her gloved fingertips into the holes. Kicking for all her worth, she stretches out another hand, clawing at the ice for purchase.

Now, right behind her, Paul and Wes follow suit. Inch by agonizing inch, the divers scramble upwards. They're ascending a slippery underwater wall while being buffeted by an enormous down current and freezing cold temperatures. And yet, bit by bit, the sunlight above becomes brighter, and with a final kick, they resurface.

When I got back to the boat and I was ready to climb the boarding ladder, I looked up and there was our head scientist, Greg Stone, and he's looking down on me. And he said, "Whoa, we were scared. What happened?" And I looked up to him and I said, "Greg, the cave tried to keep us today." And I climbed back on the boat.

And it's only once you're sort of back on the boat that that wave of emotions kind of strikes and you realize the magnitude of what you just experienced. In the end, our one hour, you know, dive that was planned turned into this three hour fight for our lives. Later that evening, sitting around a table below deck, Jill, Paul and Wes are quiet, pensive and exhausted.

There was an air of gravity about what had just happened. And I remember thinking, oh, we're not going to do another dive here. You know, that's, it's just not going to happen. And we sat down and Wes said, I got some great footage, but I really feel like to put the icing on the cake, I need one more dive. It's hard to believe given what they've just been through, but Wes isn't done yet. He seems determined they should go back under one last time.

So he was trying to justify why it was safe to get back in the water. And I remember feeling kind of doubtful, but he was convinced that we needed to do this. And as we sat around that table, striking up this plan and thinking about whether this was a good idea, we heard screams on deck. And I thought, what? But it was, you know, blood curdling enough that we dropped our forks and literally ran up the companionway so quickly that I didn't even grab a camera.

So literally before our eyes, the iceberg was disintegrating.

these sheets, these entire faces of ice were breaking away from the iceberg and crashing into the water and throwing up these giant waves that were now buffeting the boat. And we were hanging on for dear life as the entire iceberg we had just been inside of was literally exploding. And within a matter of minutes,

It was a sea of broken pieces of ice and slush as far as the eyes could see. The cave that I had just been inside of and was like planning to go back into, it was gone. Mother Nature is giving us every warning that she possibly can. It's time for us to go home.

In the months that follow, the team are fated for their daring expedition. Their film and article for National Geographic are both successes. Jill goes on to become one of the world's most celebrated cave divers. But she still looks back on the lessons learned in the Southern Ocean. Lessons that have kept her alive since.

There's so many accidents that happen on the last day of a project, a last day of exploration. And it's because of the pressures from those around you. It's because of the deliverables that you're supposed to bring back and you feel the weight of everything on top of you. And so I often leave one in the bag and I don't do the last dive. And I say, you know, I've had a great trip. I've had a great expedition and I'm just going to leave it at that.

Oftentimes journalists will write about me and they'll say fearless. I've seen that so many times in headlines. I'm like, I'm not fearless. I'm scared every time I go diving. I want to dive with people that are similarly afraid because it means that we care about the outcome of what we're doing. It means we want to come home to our loved ones at the end of the day.

You've got to immerse yourself in it. Step into it so you're not running from it. Because as you step into that darkness of something that you've never done before, something that's new and edgy and maybe scary, that's where you stand on the threshold of discovery. And I will continue to take risks, but I'll do them in the most thoughtful way that I can because I believe that what I'm doing matters. Next time on Real Survival Stories...

We meet English couple Pete and Pat Etheridge, who in 2004 are torn apart by one of the most terrible natural disasters the world has ever seen. I had no idea of what had happened. I didn't know it was a tsunami. I didn't know the world was coming to an end for some reason. I've got no idea. I twisted round to the right and there's a wall of black coming instead of the view of the sea through the trees. As Sri Lanka is engulfed by a devastating tsunami,

the Holiday and couple will face their own individual battles to survive, before they can even begin to find their way back to each other. That's next time on Real Survival Stories. Listen right now without waiting a week by subscribing to Noisa Plus.