Richard Kachkar, 46, is on trial in the death of Sgt. Ryan Russell, 35, and he has pleaded not guilty to first-degree murder and dangerous driving.
EMS worker Shannon Willis says she got a call at 6:09 a.m. on Jan. 12, 2011 that a police officer had been hit by a plow and shots had been fired.
Court has heard that Kachkar drove straight at Russell as the officer fired in vain at the plow and Russell was hit and died from head injuries.
Willis says as she approached the scene in an ambulance she saw Kachkar in the plow and he yelled at her about shots being fired and something about the Taliban.
She says her impression was that he was emotionally disturbed, not on drugs or alcohol.
Court has heard that only a trace amount of cannabis was found in Kachkar's system.
The judge has told the jury that there will be no dispute that Kachkar was the person driving the plow, rather the case will centre around his mental state. The Crown alleges Kachkar meant to kill Russell.