A modified handgun and the poor condition of its holster could have allowed an inmate to grab the weapon during a scuffle with a prison officer in a car park, an inquest has been told.
Matthew Lothian died by suicide on January 6, 2021 while being escorted wearing hand and ankle-cuffs to a medical appointment in Wollongong.
The 37-year-old had been incarcerated in Nowra after being arrested for common assault and choking without consent, counsel assisting Rob Ranken told the inquest into the death on Monday.
At the time, Lothian had been on parole after being sentenced for larceny, assault occasioning actual bodily harm and police pursuit.
After stepping out of the correctional services vehicle in the Piccadilly shopping centre car park, the inmate lunged at one of the prison officers, seizing her silver handgun.
He left the car park and fired two shots, hitting a passing police car and an 8.5-tonne truck.
Lothian then took his own life, the inquest was told.
NSW State Coroner Teresa O'Sullivan will examine the adequacy of prison policies and procedures, in particular around the inspection of firearms and their holsters.
A police investigation discovered the holster of the prison officer escorting Lothian was in poor condition, which meant the weapon was not held in place as securely as it should have been.
The gun was also fitted with an after-market grip that prevented it from sitting tightly within the holster, Mr Ranken said.
Questions will also be raised about whether a restraining belt should have been used during the escort and whether the prison officer got too close to Lothian.
The adequacy of the 37-year-old's mental health treatment plus any stressors he experienced in the lead-up to his death will also be examined.
"Why me Mum? Done. I'm over it. I'm over everything," he said to his mother during a phone call on the day he died.
Lothian had a long criminal history, going in and out of custody for property and drug offences, the inquest was told.
He was diagnosed with depression in 2013 and developed a dependence on opioids and methadone.
Weeks before his death, he was spotted upset, restless and agitated and was monitored by medical staff and a psychologist for risk of suicide or self-harm.
He had been escorted to Wollongong to have surgery after being assaulted in his prison cell, suffering facial fractures, a broken nose and a black eye.
He denied he had been beaten up, claiming he had run into a door playing football.
Lothian had also said he had connections with the Hells Angels bikie gang but later retracted those statements, Mr Ranken said.
In August, the coroner called for an urgent review of legislation regarding correctional officers' use of firearms following an inquest into the shooting death of Dwayne Johnstone while fleeing custody.
The inquest into Lothian's death continues.