John Hopkins

A tether is made to clip him to the shot line in case he loses consciousness, and a rotor is agreed to ensure at least one diver remains with him at all times.

But despite this, Don's situation remains dire.

It's been a couple of hours since he entered the water, but as he nears the surface, his decompression stops need to become longer and more frequent, meaning he still has more than 10 hours to go.

The climb is grueling.

Don's throat and stomach are raw from retching, and it takes all his strength to maintain his grip on the shot line.

But even as he edges laboriously closer towards the light and air, this strength is fading.

Too weak and dizzy to maintain a diver's usual horizontal position, which allows gas to flow directly into the lungs, Don is forced to breathe vertically.

Soon, every inhale is a painful effort.

Don is forced to press his regulator's purge button with each inhale, which helps to push a stream of gas into his lungs.

It's all that's keeping him alive.

And then, when the surface is tantalizingly close, there is another problem.

He's struck by a new, terrifying pain.

A sharp stab in his left knee, a classic sign of the bends.

There's no more time.

After some negotiation with the medics, Don agrees to cut his decompression in the water short and take his chances on dry land.

And so, 12 and a half hours after beginning his dive, he finally lets the team pull him from the water and into the warm evening air.

Utterly depleted and unable to walk, Don is placed on a gurney, then hoisted up the slopes with a rope and pulley system and taken to the mobile recompression chamber above.

He is mated out of Bushman's Hole, but that doesn't mean his battle is over.

He remains in the claustrophobic, oxygen-rich chamber until the early hours of the morning.

When he is eventually able to emerge, it becomes clear quite how serious his condition is.