An Australian doctor convinced\u00a0Thai\u00a0officials to change their rescue plans and first get some of the weakest boys out of the cave where they were trapped, it can be revealed.\u00a0\r\nCave diver and\u00a0anaesthetist Dr\u00a0Richard Harris, from\u00a0Adelaide, dived with the rescue team on Sunday afternoon to check on the 12 boys and their coach.\r\nThe initial strategy was to extract the strongest boys first because they would have more chance of making it to safety while the others could stay back and build up strength.\r\nBut that was revised after Dr Harris' health assessment found some of the weaker boys may not survive if they were left behind, according to Thai media.\r\nFour of the 12 trapped boys were brought to safety on Sunday evening. Operations to bring out the other eight and their coach will start this afternoon as divers place fresh oxygen tanks along the exit route.\u00a0\r\nDr Harris, who was requested by British divers leading the operation, is working alongside the Thai Navy and 18 other Australians in the rescue efforts.\r\nThe 53-year-old has 30 years of diving experience and has worked on retrieving bodies from caves.\r\nHe famously found the body of stunt diver Agnes Milowka who ran out of air in the Tank Cave near Tantanoola in the south east of South Australia in 2011,\u00a0The Advertiser\u00a0reported.\r\nDavid Strike, a dive event organiser who has known Dr Harris for more than a decade told\u00a0Fairfax:\u00a0'He's been diving for over 30 years, and readily embraced advances in diving technology to better help him explore and photograph caves in Australia and overseas.'\r\n'In the past few years, he's been involved in cave-diving explorations in Australia, China, Christmas Island and New Zealand. He has an active interest in diving safety and accident investigation.\r\n'Quite apart from his own cave exploration experiences, as an anaesthetist and a medical professional who is also involved in retrieval medicine, he has always struck me as a person who is capable of calmly assessing any situation and then acting appropriately.'\u00a0\r\nThe 'extremely dangerous' operation to free the boys, who have been trapped in the cave for 15 days, began on Sunday morning when rescuers decided to act before more monsoon rains flood the caves.