An Australian doctor with 30 years of cave-diving experience wouldn't have hesitated for a second in joining a rescue mission to save a young Thai soccer team from their cave prison, his colleague and boss says.
Adelaide anaesthetist and underwater cave explorer Richard "Harry" Harris risked his own life on Saturday to make the treacherous journey to the chamber where the boys have been trapped underground for 15 days.
He's been described as "essential" to the rescue bid because of his unique skills and experience, which includes his work as a medical retrieval specialist with South Australia's MedSTAR emergency service.
"He's an interesting character," MedSTAR clinical director Andrew Pearce told reporters on Monday as the rescue efforts in Thailand continued.
"Harry is selfless, he is extremely thoughtful. He's a quiet person. He is the type of guy who will give of his all.
"He was actually meant to be on holiday and gave up his holiday so that he could be part of this."
Dr Pearce said Dr Harris was known globally both for his work as a doctor and his ability to retrieve people from difficult places.
"He's using those skills at the moment, not only as a doctor but the added benefit that he happens to have this amazing ability to do what no-one else does in diving into very dark, tight spaces with not a lot of equipment," he said.
"In this small fraternity of people, when you get asked for by name you're known worldwide for your skills."
Dr Harris, who has 30 years of diving experience, is also well known in the cave diving community, including as the leader of record-breaking missions to explore a dangerous underwater cave system on New Zealand's South Island.
In 2011 and 2012, he led a team of Aussie divers to record depths of 194 and 221 metres in what's believed to be one of the world's deepest cold water caves, searching for the source of the Pearse River.
He filmed the dangerous and complex mission for National Geographic.
It required the team to set up a series of survival pods at intervals to allow divers to decompress, rest and eat in the near-freezing waters along the length of an underwater river - an experience that could prove invaluable in the current rescue mission.
Foreign Affairs Minister Julie Bishop said Dr Harris had been essential to assessing the health of the trapped boys.
"He is an experienced diver, which is a great benefit because he's brought all that expertise to assist the Thai government in this rescue mission," she said.
It was on his advice the first four boys were cleared to make the incredibly dangerous journey out of the flooded cave complex, emerging alive on Sunday.
The rescue divers and boys in Thailand must dive, swim and climb their way to safety along a pitch-black tunnel that at certain points is barely big enough to allow an adult to wriggle through.
Australian Associated Press
