A full-time national serviceman (NSF) who died of heatstroke in April 2018 was taken to a medical centre about 40 mins after he was seen with signs of heat injury, investigations revealed.

The delay in the evacuation was a contributing factor in Corporal First Class (CFC) Dave Lee Han Xuan's death, the state coroner heard yesterday in an inquiry into the NSF's death.

CFC Lee, then 19 and a guardsman from the 1st Battalion Singapore Guards, collapsed right after completing a 8km fast march at Bedok Camp on April 18.

He was later admitted into Changi General Hospital (CGH) and died on April 30, 2018.

The late Singapore Armed Forces (SAF) Captain Tan Baoshu, who was the supervising officer of the fast march, was charged in October 2018 with causing death by performing a rash act. He was also accused of disallowing the necessary treatment for CFC Lee.

Tan, 33, was given a discharge not amounting to an acquittal in January last year, after he was diagnosed with stage 4 cancer. He died on Feb 13 last year.

Station Inspector (SI) Aliden Hamad, the investigation officer on this case, said CFC Lee was observed to be incoherent, breathing heavily and drooling after he crossed the finishing line at 8.25am. Ice packs were applied to his body and water sprayed on his face. He was given isotonic water but was unable to swallow it.

SI Aliden said the medic for the fast march failed to diagnose CFC Lee as having heat injury. He added that Capt Tan rejected suggestions from other army personnel to evacuate the NSF to the camp's medical centre, saying the soldier was only suffering from physical exhaustion and would recover after resting.

The officer also rejected a suggestion for CFC Lee to be administered an intravenous drip and instead directed that a ground sheet be used to cover the NSF.

The officer later ordered for CFC Lee to be evacuated, and he arrived at the camp's medical centre at around 9.05am.

Despite receiving medical treatment at the centre and later at CGH, he eventually died.

SI Aliden said the delay in evacuation was a contributing factor in his death, but no foul play is suspected.

Dr Kenneth Heng, who was appointed to give an independent medical report, said covering CFC Lee with a ground sheet was counterproductive. The NSF would not have been able to sweat, he said.

He added that CFC Lee should have been moved to a shady area and fanned with his shirt removed to increase sweat evaporation.

Evacuating him to the medical centre should have been a priority, with a 40 min delay to do so "too long", the doctor said, noting that a 10-15 minute delay would have been reasonable.

Noting that CFC Lee's platoon was made to do physical activities including push-ups the night before, he said the exertion and subsequent reduced rest might have contributed to the heatstroke.

State Coroner Kamala will give her findings on Jan 27.

Since the case, the SAF has introduced enhancements to existing heat injury management and prevention measures, such as a simplified evacuation protocol.

Six other SAF servicemen were charged in military court over CFC Lee's death and were last September fined between $1,800 and $4,500 each. Three of them were also demoted from the rank of third sergeant (NS) to corporal.