In the aftermath of a troop carrier crash that would kill a fellow army sapper and injure six others, Alexander Gall allegedly said, "I'm done, I was going too fast".
The 20-year-old had been driving the Mercedes-Benz Unimog back to base at a Sydney army barracks when he lost control on a left-hand curve, and the vehicle turned over.
He had finished his training to drive the six-tonne carrier five days earlier.
The 15 passengers in the back were thrown from the vehicle and one of them, 22-year-old Sapper Jordan Penpraze, died in hospital three days later.
Gall, now 24, is on trial over the October 8, 2012 crash, having pleaded not guilty to one count of dangerous driving causing death and six counts of dangerous driving causing grievous bodily harm.
Crown prosecutor Brian Rowe alleged in his opening statement on Tuesday that the crash was caused by Gall's speed, with one passenger in the front cabin saying, "you might want to slow down".
Mr Rowe said the vehicle reached speeds of 80km/h on the unsealed gravel road, and concerned passengers in the back tried to get Gall's attention so that he would ease up.
He said a passenger heard Gall say after the crash, "this is all my fault, these people are going to die, I'm done, I was going too fast".
Video played to the jury showed personal packs, clothing, guns and debris from the vehicle strewn on the road, in a tree and in surrounding scrub after the crash.
The court heard that one month earlier, on September 4, Gall had begun his training to drive Unimogs at the Army School of Transport in Victoria, having previously only held a learner's automatic licence.
He finished his training on October 3, five days before the crash, court documents said.
Gall's barrister David McClure SC said that only 13 days of Gall's course involved driving, and that everything he knew about driving Unimogs he knew from the army.
"The army's training of this man was hopelessly inadequate and the supervision of him at the time of the accident was almost non-existent," he said.
The trial continues.