John Hopkins

After the bodies are retrieved, attention turns to the camera Dave was wearing.

The footage shows his dive went entirely to plan until he tried to place Dion into the body bag, at which point both he and the body became unexpectedly ensnared in the cave line.

During the struggle to free himself from the tangle, Dave's breathing grew heavier, increasing the amount of CO2 he was emitting into his rebreather.

As Don reckons with the loss of his friend, he is also struggling with his own physical recovery.

The effects of his decompression sickness are so bad that it's feared he may never walk normally again, let alone dive.

In the days that follow, he endures several sessions in the recompression chamber before Andre drives him for further treatment at a hospital in Pretoria.

Though Don shows incremental improvement after each session, progress is dispiritingly slow.

Yet, despite his debilitating symptoms, his determination to get back to diving propels him forward.

Only a matter of months after the tragic events at Bushman's Hole, he tries re-entering the water at Kamati Springs for the first time.

Despite everything, Don has returned many times to dive at Bushman's.

In the years since the accident, he's had plenty of time to reflect on his near-death experience there and on what enabled him to survive.

In the end, Dave did fulfill his promise to recover Dion's body, though he paid the highest price imaginable for it.

At the behest of Dave's widow, Don scattered his friend's ashes near his home at Kamati Springs.

The place where they first dived together, and where, two decades later, Don continues to dance in the water, both for himself and for Dave.

In the next episode, we meet Mayan Sabag.

In 2008, the 27-year-old is studying in the Chinese city of Chengdu.

One day, her friend suggests they escape the hustle and bustle and head to a remote nature reserve.

But while passing through a village nestled in the mountains, they suddenly find themselves at the epicenter of a terrible natural disaster.

A magnitude 8 earthquake that will go down as one of the deadliest in human history.

When the restaurant they're sitting in collapses, Mayan is trapped in the pitch black, buried alive, and so badly injured she's unable to even call out for help.