Tjay Robert Doeblien, 27, died after being shot in the chest by a police officer outside an Ipswich home, west of Brisbane, in May 2022.
Police had responded to reports of a disturbance and a male chasing a female with a stick, Coroner Terry Ryan heard at the start of an inquest on Wednesday.
Senior Constable John Johnstone testified he fired his service rifle at Mr Doeblien after the man's statements and his pointing a firearm at officers helped him decide there was a deadly threat to police.
"I decided to attempt to stop that imminent threat. I pressed the trigger once, opened fire once and reattained a sight picture," Sen Const Johnstone said.
"He was still standing in the same way. That meant my risk assessment hadn't changed. I pressed the trigger again and ceased firing. I observed him fall."
Mr Doeblien's mother Patricia Roach and family members were in court for the inquest and saw body-worn camera video of police trying to negotiate.
"You put the gun down, we lower our firearms. That's a fair deal," one officer said in the footage.
Mr Doeblien had a crude "zip gun" he made from a pipe, metal plates and a wooden grip covered in tape and painted silver, a police ethical standards investigation found.
"It had no firing pin. It was incapable of being fired. It looked like it was real," Detective Senior Sergeant Tara O'Donnell testified.
It seemed Mr Doeblien had a silver handgun in his hand, Sen Const Johnstone testified.
Mr Doeblien was walking around, pointing a gun at himself and police and told officers "there's one round in here and one of you is going down", Senior Constable Darien Gough said.
A person pointing a gun at officers 25 metres away was determined to be an unacceptable risk of death or serious harm to police or the public, Mr Ryan heard.
"He made a direct threat that one of us was going down. I interpreted it as one of us would be shot and killed," Sen Const Gough said.
Mr Doeblien was repeatedly told to put his gun down and did not comply, but yelled at police his gun did not have a firing pin.
Sen Const Gough said he still prepared to use lethal force with his police-issue pistol.
"It doesn't change the risks. We didn't have that establishment of trust," he said.
Sen Const Gough saying "he's got one bullet. If he points it, we have just got to deploy, mate" did not act as encouragement to shoot, Sen Const Johnstone testified.
"I believed (Mr Doeblien) had the capability of killing or seriously injuring any of us present," Sen Const Johnstone said.
"When he used both hands to point in our direction, I thought he was imminently going to shoot that firearm and possibly cause death or grievous bodily harm."
The inquest is due to conclude on Thursday.
Lifeline 13 11 14
beyondblue 1300 22 4636
14°C