The 12 boys, aged between 11 and 16, and their coach became trapped on June 23 when they were cut off by floodwaters while exploring the cave. "They talked to the boys far away from them, about 2 meters [6.5 feet]", Thongchai said.
Thai doctors have said they did not know what type of unusual illnesses the boys may have picked up in the cave. Some of them, wearing surgical masks, lay on their beds.
None of the boys was heard speaking in the clips shown at the news conference.
A Thai health official said earlier Wednesday that the soccer teammates had lost weight during their two-week ordeal, but had water while they were trapped and remained in good health.
The video footage shows how engineers preparing for the operation had carved neat steps into steep slopes in the tunnels to make it easier, although they were cascading with water. Authorities are anxious about the possibility of infections picked up in the cave.
Prime Minister General Prayut Chan-o-cha, who visited the rescued boys on Monday night, confirmed yesterday that the stranded footballers were given medication to prevent anxiety and panic - identified as a key danger - while being evacuated.
"What was really important was the coach and the boys all came together and discussed staying strong, having the will to live, having the will to survive", Anderson said. "The best way is not to bother them and let them study".
Later this week, the Discovery Channel will be airing a one-hour documentary chronicling the team's weekslong ordeal: "Operation Thai Cave Rescue" premieres at 10 p.m. ET/PT on July 13.
The most risky part of the journey out of the labyrinthine cave system was the first kilometer, during which they were required to squeeze through a narrow flooded channel.
Boys Rescued from Thai Cave in Good Health
The rescue efforts cost the life of one rescue worker - a former Thai Navy Seal ran out of air inside the cave system. Rescue mission chief Narongsak Osottanakorn said: 'We don't see the children as at fault or as heroes.
Narongsak, giving details of the rescue, said falling oxygen levels inside the cave complex had added a sense of urgency.
At U-Tapao civil-military airport in Rayong province, near where the Royal Thai Navy operates out of Sattahip Naval Base, Thai navy SEALs and some foreign military personnel were given a hero's' welcome when they touched down on Thursday.
The unprecedented mission was completed on the 18th day of an all-out rescue effort involving several countries from around the globe. "For SEALs, this is what we were trained for".
The rescue has dominated front-page headlines in Thailand and beyond for days. "Mission accomplished" and the Bangkok Post emblazoned with "All Wild Boars saved".
The Brits who discovered them were among the elite divers who flew out after the Thai authorities begged the world for help. This means they will not be able to take up the invitation from Federation Internationale de Football Association to attend the Soccer World Cup final in Moscow.
Nopparat Kanthawong, the head coach of the Wild Boars team, told CNN that he did not know why the boys had gone into the cave.
At least three of the boys in the team as well as their coach are stateless refugees and might have restricted travel rights, Reuters has reported.
A Google search on Tuesday for the words "Thai cave rescue" revealed 359 million results.