The Australian doctor critical to the Thai cave rescue received the heartbreaking news his father had died after he emerged from the flooded tunnels.
A colleague of Dr Richard "Harry" Harris said Wednesday the Australian cave diving doctor is exhausted after a tumultuous week and now needs time to "decompress".
Dr Harris played a key part in the rescue of 12 Thai boys and their soccer coach from a flooded cave system, only to find out he lost his father just hours after helping the boys to safety.
In a press conference, MedSTAR's director of clinical services Dr Andrew Pearce said the death of Dr Harris' father was unexpected.
Dr Harris, an Adelaide anaesthetist with more than 30 years' cave diving experience, swam 4km through cold, submerged tunnels to make contact with the stranded team and provide medical aid.
It’s understood Dr Harris was the last person to come out of the cave after assessing the remaining four boys and their coach.
Earlier in the day, South Australian Ambulance released a short statement, confirming the news.
"It is with great sadness that I confirm that Harry’s dad passed away last night a short time after the successful rescue operation in Thailand," Dr Pearce said in the statement.
"I have spoken with Harry. This is clearly a time of grief for the Harris family, magnified by the physical and emotional demands of being part of this week’s highly complex and ultimately successful rescue operation."
Dr Pearce said the experienced diver was a "quiet and kind man" who "did not think twice about offering his support on this mission".
Praise for Aussie medic
There were 20 Australians who took part in the rescue, but Dr Harris' efforts have received particular praise from acting Chiang Rai governor Narongsak Osotanakorn.
"(The Australians) have been a big help, especially the doctor," Osotanakorn told 9NEWS.
"Very good. The best – not good – the very best."
The 53-year-old medic was also been singled out by the Australian government, with a joint statement from Foreign Minister Julie Bishop, Defence Minister Marise Payne and Home Affairs Minister Peter Dutton praising him.
"Australia has played an integral role in this unprecedented operation. We congratulate all of those involved, including Dr Richard Harris and his dive partner Craig Challen, as well as our Australian Federal Police divers and personnel from the Australian Defence Force and Department of Foreign Affairs and Trade who provided logistics and planning expertise,” the statement read.
"Australia has been proud to work with Thailand and other countries to achieve this extraordinary outcome. "
Dr Harris was the medic who made the call for the team to be swum out after assessing them last week.
Authorities were exploring multiple options to get the 13 Thais out, including tunnelling in or providing them with enough supplies to wait out the monsoon season.
However, limited air and the likelihood of more heavy rain saw the timeline step up.
The Australian doctor made the challenging swim through the extensive network of flooded tunnels to ensure the children – none of whom had any dive training – were physically up to the 1.7km trek out.
He also administered a sedative to the boys to calm them for the epic exit.
Thailand's Prime Minister Prayuth Chan-ocha said the boys were given mild anti-anxiety medication before they swam through the tunnel complex in order to help them relax.
"It's called anxiolytic, something to make them not excited, not stressed," he told the Associated Press when asked at a press conference on Tuesday.
The British divers who made the initial contact with the trapped boys and their coach last Monday specifically requested the Australian medic after the rescue attempt claimed the life of a former Thai Navy Seal.
It’s not the first time Dr Harris has been involved in a fatal rescue operation.
The experienced diver was also called in to recover the body of friend Agnes Milowka, who ran out of air while diving in Tank Cave, South Australia, in 2011.
South Australian police also specifically requested Dr Harris to tackle the 8km underwater stretch.
Alongside the doctor, 18 other Australians formed part of the international contingent assisting the rescue operations, including Australian Defence Force specialists and Australian Federal Police divers.