A former Thai navy Seal diver who volunteered for an operation to rescue a football team trapped in Tham Luang cave died yesterday, as the Thai authorities warned that they have a limited amount of time to free the group.
Mr Saman Gunan, 38, passed out as he was making his way out of the cave after placing oxygen tanks deep inside the underground complex. His diving partner took him back to "chamber three", where the Thai navy Seals have set up a base, to try to resuscitate him. But he died at 1am local time.
His death highlighted the risks of bringing the 12 boys and their football coach out through the cave's cramped, flooded passageways - a journey that takes experienced divers about five hours or more.
Intermittent rain hit the area yesterday and more downpours have been forecast until Wednesday, hindering efforts to drain water from the cave system.
"We can no longer wait for all conditions (to be ready) because circumstances are pressuring us," said Thailand's navy Seal commander Apakorn Yookongkaew. "We originally thought the boys can stay safe inside the cave for quite some time, but circumstances have changed. We have limited amount of time."
The trapped team are being taught how to swim and dive in case the order to evacuate is given.
Officials have been hoping that the water level would recede enough to allow the group to trek or crawl at least part of the way.
But another complication emerged yesterday when the Thai authorities said oxygen levels have dropped due to the number of people working in the cave. Some have been bringing in food and supplies, while others are preparing the route that the group might have to take.
Rear-Admiral Apakorn said a doctor was with the boys and their coach to monitor their health.
Mr Ivan Karadzic, 44, a Danish volunteer cave diver who arrived at Tham Luang this week, described the challenges faced by rescuers. He dived in the cave for the first time on Thursday, and told The Straits Times that it was "incredibly exhausting". The visibility in the water was also very poor.
"You need to walk about 90 minutes to where you can dive. It was a very difficult walk because of mud and narrow passages. It took me eight hours to travel from the entrance to the T-junction and back."
Mr Karadzic, a diving instructor who has lived in Koh Tao Island in Thailand for 11 years, said he is worried about the boys' dive training.
"There is no way to train kids to become cave divers. It is impossible... You cannot spring to the surface in cave diving, which is different from the usual diving," he said.
But he said there are people who have experience rescuing children from deep inside a cave, and he told Sky News that the rescue could happen "today or tomorrow".
Meanwhile, billionaire entrepreneur Elon Musk tweeted yesterday that engineers from his firms - SpaceX and The Boring Company - were heading to Thailand to see if they could assist in the rescue. The Boring Company has "advanced ground penetrating radar" and is "pretty good at digging holes", he said earlier. It could also provide heavy-duty battery packs if needed.