A teenager doing army recruitment training "went blank" before letting go of a ladder and falling metres into a flooded tunnel, a NSW inquest into his death has heard.
Private Liam Wolf, 18, died two days after the fall, on April 21, 2019.
Pte Wolf likely suffered a cardiac arrest and then sustained a brain injury in the fall, expert witnesses are expected to tell the NSW Coroners Court.
The Queensland man was nearing the end of the army's 80-day basic training course for new recruits at Blamey Barracks in Kapooka, in the NSW Riverina.
The recruits rose at 4am, marched five kilometres with weighted packs, and were completing an obstacle course designed to test the resilience and teamwork skills they'd been building.
Gabrielle Worth, a fellow recruit and Pte Wolf's battle buddy during the 12 weeks of training, had climbed the four-metre metal ladder out of the tunnel, then crouched to watch him ascend the ladder behind her.
"About halfway up, his face just goes blank," Pte Worth told police in a taped interview.
"His eyes are wide open but they're not seeing anything ... then in a split second he just lets go."
He fell flat into the tunnel, which was filled with ankle-deep water, with his F89 Minimi gun slung on top of him, his eyes open, and blood on his head.
Pte Wolf's fellow recruits and army staff performed CPR and lifted his head above the water in a desperate attempt to save his life.
A dozen people helped to stretcher him out of the underground tunnel, before emergency services took him to Wagga Base Hospital and then by helicopter to Sydney.
Pte Wolf had been moving through the obstacle course slower than normal, Pte Worth thought.
But she said he was a quiet person and not the type to complain.
She described the obstacle course as stressful because it was the culmination of all their training.
"The whole time you're working towards this day and it's been drilled into you that this is the day for you to shine," Pte Worth said.
Though the focus was on good technique, recruits were timed as they went through the obstacle course and a prize awarded to the section which could complete it the fastest.
Over the 12 weeks of training Pte Wolf was treated twice for viral illnesses, the inquest was told on Monday.
He was just 17 when he signed up for the army. An award has been created in his name for the army recruit with the best rifle shot.
Deputy State Coroner Derek Lee and lawyers went to look at the tunnel and barracks firsthand in April.
The tunnel has not been used since Pte Wolf's death.
