A negligent driver who stole and fired a police officer's gun inside Canberra Hospital is an "absolute coward" who could have killed someone, a senior constable has told a court.
ACT Policing's Senior Constable Steven Salleo and First Constable Douglas Kinley took the witness stand on Tuesday in the matter of James William Shearer.
Shearer previously pleaded guilty to several charges, including assault occasioning actually bodily harm, negligent driving, multiple counts of endangering life, and attempted robbery.
He crashed a stolen car into a tow truck on Yamba Drive on July 18, 2018, causing two people serious injury. A witness' victim impact statement, read aloud in court, recounted how Shearer got out of the car and attempted to steal two others from nearby women.
"[Shearer] had a look on his face like he was going to murder me once he got into my car," the witness' statement said.
"I think I will be scarred for the rest of my life."
Later, under police guard at Canberra Hospital, Shearer threw a "large metal chair" at Senior Constable Salleo, the court heard on Tuesday. He snatched Constable Kinley's Glock from its holster, and ran down the hallway of the hospital's emergency department.
"I remember thinking about the gravity of the situation," Constable Kinley said in court.
Shearer went on to fire a round from the Glock at the ceiling - bursting a water pipe - and shoot rounds near both officers. A "violent" struggle ensued, and both officers believed Shearer could kill them, nearby hospital staff, or "vulnerable" members of the public.
"I recall being absolutely terrified," Senior Constable Salleo told the court.
"I remember thinking I was most likely going to be shot and killed."
While wrestling on the floor of the hospital, Shearer bit Senior Constable Salleo on his right arm, the officer told the court. He still has a scar from the assault in the shape of Shearer's mouth.
Senior Constable Salleo managed to put his finger behind the Glock's trigger and stop Shearer from firing it further. He dislodged the magazine from the gun and it went off once more.
The officer then Tasered Shearer's half-naked body. On Tuesday the court was shown footage of Shearer screaming after it was fired.
Senior Constable Salleo said Shearer's actions showed he was an "absolute coward".
"[The incident was one of] the worst forms of violence I've ever experienced," he said.
"He has shown no remorse for his selfish acts since that time."
The case is due back in court on Friday.