Most of the equipment being readied for the dive was familiar to both Shaw and Shirley, but Shaw's helmet camera -- designed by Hiles -- was new and untried.
Two days before the final dive, the full team began assembling at Bushman's Hole, each member with a specific duty. Shaw would go the deepest and retrieve the body.
"His instruction was very simple, that you know, if something did go wrong, um, nobody was to play the hero or risk their own lives to come and fetch him," said Van Schaik.
"It cannot be any other way. It's better to have one person dead than two. It's as simple as that," said Shaw.
Those were his public instructions, but privately, Shirley and Shaw had an agreement.
"The agreement was that if Dave needed me, he would… signal with a light," said Shirley.
"It's a very solemn thing when you're actually doing a serious dive you really can't have people asking you questions or doing anything," said Shirley.
Van Schaik coordinated the dive from the surface, and since this was a body recovery, police divers temporarily tagged the site as a crime scene, and spectators begin to gather. Theo and Marie Dryer were among those who came to watch.
The dive plan called for Shaw to descend to 886 feet, place Deon Dryer's body in the body bag and bring him up to Shirley, waiting at 725 feet. From there the body would be passed through a series of divers all the way to the surface, while Shaw and Shirley began their 10-hour ascent and decompression back to the top.
It was calculated that Deon's body would reach the surface 70 minutes after the start of the dive, but the 70-minute mark came and went, with no sign of the body.
"At around 70 minutes, when the police divers didn't come up, when they're expected, I thought something had gone different. Not something had gone wrong, but something had gone different to what was planned," said Van Schaik.
Five hundred feet down, Shirley was having the same thought. "I was looking down, and I would expect to see bubbles coming back up from Dave on his ascent, but I didn't see those bubbles."
Shirley said he saw only a "small pinprick of a light" that wasn't moving.
Van Schaik suspected that Shaw was suffering deep water narcosis. "He was running in a very high narcotic depth," she said. "And it affects the way you think as well. You really have to focus hard to get your mind to solve problems."
"The agreement that Dave and I had was if he had a problem, he would signal and move the light," said Shirley. "The light wasn't moving. What I thought is that, if I could get to him, then I might be able to bring him round if he'd passed out or, or something, I could bring him back."
Shirley started to descend, but at about 800 feet, deeper than he's ever gone, he suddenly heard a loud crack. It was the sound of the controller that regulated his oxygen shattering under the immense pressure. In the time it takes for a single breath, Shirley's hope of finding his friend turned into a battle to save himself.
Without his controller, Shirley had to manually control his air supply. He had no choice now but to abandon the rescue, but he was 100 feet deeper than the original plan, which had set off a chain reaction with the support divers above him.
Peter Herbst,who was to have met Shirley at 240 feet, began to descend further, looking for either Shirley or Shaw, and carrying a diver's writing slate.