The 12 boys rescued from deep within a flooded cave in northern Thailand have made victory signs from their hospital beds in a video from the isolation ward where they are recuperating after an 18-day ordeal.
The youngest boy (11) appeared asleep under a white sheet while others, including their 25-year-old football coach, sat in bed, their faces obscured by green surgical masks.
Nurses chatted with them and the boys responded with the customary Thai sign of respect - hands pressed together while bowing the head.
Excited parents watched and waved from behind a glass barrier.
Chaiwetch Thanapaisal, director of Chiang Rai Prachanukroh Hospital, told a news conference: "Don't worry about their physical health and even more so for their mental health.
"Everyone is strong in mind and heart."
The four boys and their coach who were brought out on Tuesday, the final day of a three-day push, had recovered more quickly than the boys rescued on Sunday and Monday, Mr Chaiwetch said.
Even so, all need to be monitored in the hospital for seven days and then rest at home for another 30 days. Three have slight lung infections.
Another video released on Facebook by Thailand's Navy Seals, which were central to the rescue, apparently shows one of the boys being carried through part of the muddy cave on a stretcher covered by an emergency thermal blanket.
The group had entered the sprawling Tham Luang cave to go exploring after football practice on June 23, but monsoon rains soon filled the tight passageways, blocking their escape.
They were found by a pair of British divers nearly 10 days later, huddled on a small, dry shelf just above the water, smiling with relief but visibly skinny.
The complex mission for international and Thai divers to guide the boys and their coach through the cave's flooded and tight passageways was dangerous, and a former Thai navy diver who volunteered died on Friday.
Narongsak Osatanakorn, the official overseeing the rescue operation, said the boys should not be blamed for the near-tragedy.
He lauded the co-operation between Thai and international rescuers.
"The situation went beyond just being a rescue mission and became a symbol of unity among mankind," he said.
"Everyone worked together without discrimination of race or religion, as the ultimate goal was to save the youth football team."
Each of the boys, aged 11 to 16 and with no diving experience, was sedated to be guided out by divers though rocky, muddy and flooded passages.
The method was extremely risky, but dwindling oxygen levels in the cave and fears of more monsoon rains to come made a decision urgent.
Relatively mild weather and a massive effort to pump out water created a window of opportunity. The confidence of the team, and expertise specific to the cave, grew after its first successful mission on Sunday.
Thongchai Lertwilairatanapong, a public health inspector, has said that the boys lost an average of 4.4lbs (2kg) while they were trapped. Before their discovery, they survived by drinking water dripping into their cramped refuge.