Christopher Betts, 34, died from a gunshot wound to the head in Sun McKay's Baghdad dorm room on May 12, 2016.

Australian Federal Police found Mr Betts' death was self-inflicted but could not determine if the cause was suicide or misadventure.

The medic and bodyguard to two Australian ambassadors stood by what he'd told investigators after the shooting - saying Mr Betts "actioned" the Glock 17 pistol, held it to his head and said "it's time to play clear or not clear" before pulling the trigger.

He said denied claims by multiple colleagues that sloppy weapons handling and booze were a factor

"I am certain if he was just f***ing he would have just stopped and looked at me ... to see what reaction he got (but) I am sorry he did it incredibly quick," he told the Brisbane Coroners Court on Friday.

Mr McKay said after Mr Betts died his only thought was for his mate.

"My main goal was to try and protect Chris. If it had been an accident may be the insurance would pay his family," he said.

The inquest concluded on Friday.

Coroner Terry Ryan is expected to deliver his findings in January.

Australian Associated Press