Then-leading senior constable Timothy Baker pulled over Vlado Micetic, 44, at Windsor on August 25, 2013, the Coroners Court was told on Monday.

He says he acted in self-defence when he shot Mr Micetic three times to the stomach after Mr Micetic pulled out a spring-loaded knife.

"He believed he was going to be stabbed and due to the close approximately he had no alternative to shoot him," counsel assisting Rachel Ellyard said.

Mr Micetic had stepped out of the car and was complying before it was alleged a scuffle with the officer unfolded.

"What you doing this for? You are going to get in big trouble. You are going to lose your job," Mr Micetic can be heard saying in vision played to the inquest before three shots ring out.

Following the shooting, Mr Baker was suspended from duties before resigning and was later cleared of murder by a jury.

The inquest heard Mr Baker could not pass a training course in 2012 due to shaking hands, his operational duties had been suspended while getting treatment before he was allowed to work again.

His return to work in 2013 came after he was diagnosed with post-traumatic stress disorder.

He was allowed to work alone conducting traffic patrols - similar to his peers - and carry a gun, the court was told.

"It is not clear what degree, if any, of monitoring he was under on his return to work," Ms Ellyard said.

Mr Baker also suffers a depressive illness and alcohol dependency.

Some of his medication had been changed recently prior to the incident.

Retired inspector Stephen Beith told the inquest he was not aware of any health conditions of Mr Baker until after the shooting.

"During my career I have known a lot of police would drink and would be alcoholics. But they would also front up the next day and you would not know they are alcoholics," he added.

"It would have to be quite strong evidence given to me to change his rostering."

During the fatal incident, Mr Baker called for an ambulance and Mr Micetic was taken to hospital having a cardiac arrest.

"Two minutes and 48 seconds had elapsed between the time Vlado got out of the car and he was shot," Ms Ellyard said.

Investigators found three spent casings, a knife with a spring-loaded blade, a phone, keys and safety flag at the scene.

Mr Baker said he moved the knife without using gloves at the scene. Mr Micetic's female passenger told police she did not see a knife.

The inquest continues on Thursday.

Australian Associated Press