But two days later, the 20-year-old Republic of Singapore Air Force trainee technician's condition took a turn for the worse and he died at Changi General Hospital (CGH) on Nov 24.

State Coroner Victor Yeo on Thursday ruled the death an accident, concluding that Liu had suffered from pneumonia and multiple organ failure as a result of a heat stroke.

Investigations also showed that there had been no foul play and no lapses in the conduct of the individual physical proficieny test (IPPT) which Liu was taking at the time.

Mr Yeo said, 'The immediate medical attention given to the deceased was prompt and appropriate.'

Liu's parents were not in court for the inquiry.

However, in a telephone interview later, Mr Lew Sin Huat, 54, told The Straits Times that he and his wife did not go to court as they already sensed the verdict.

'He was a very healthy boy. We are very sad. We are reminded of him every day when we walk past his room, which is left the way it was before he died,' he said.

Liu was at the Air Force School at Airport Road that morning and had completed the four static stations required to pass the test.

These include the sit-up, standing broad jump, chin-up and 4 x 10m shuttle run.

Those taking part were given a 20-minute break before doing the 2.4km run, and they were asked to drop out from the test if they were feeling unwell.

About five participants dropped out, but Liu carried on with the run, which began at about 9am.

Just as he was about to cross the finish line, he was seen running in a zig-zag manner and suddenly collapsed.

A standby medic immediately gave him cold water and fanned him before a safety vehicle came and took him to the Paya Lebar Medical Centre, about 500m away.

At the centre, Liu was observed to be unresponsive and was only able to move his limbs and open his eyes in response to pain.

His body temperature at the time was deemed high at 39.7 degrees celsius. His clothes were removed and ice packs were placed on his forehead, armpits, neck and groin area before he was sent to CGH.

In the ambulance, he regained full consciousness and was later placed in a body-cooling unit at the hospital to lower his temperature, which at the time was about 40 degrees celsius.

Half an hour later, he began to show signs of improvement and was placed under observation.

His condition was stable over the next two days before doctors found a deficiency of oxygen in his body. It was downhill from then on, until he died - ten days after he collapsed.