Smith was 19 when she died in October 2007 after she tied a ligature around her neck in her cell at the Grand Valley Institute for Women in Kitchener, Ont.
Asked why he didn't step in, Valentino Burnett said that he might have been disciplined if he had disobeyed an order not to intervene when the 19-year-old Moncton woman choked herself, something she had done many times before.
Guards had been told Smith's actions were a ploy for attention, and that they should stay back.
"If an order is given to me and I don't agree with it, there's a grievance procedure," he said on Tuesday during his second day of testimony.
Burnett and three other prison employees were charged in Smith’s death, but the charges were dropped.
Video shows events leading up to choking
On Monday, jurors saw a video that shows guards watching as Smith choked to death with a piece of cloth tied around her neck as she was face down in her cell.
When the recording begins, the guards had been debating for about 10 minutes about what to do about Smith. The guards had been told she was seeking attention, and not to intervene unless she stopped breathing.
Smith could be seen wedged between the bed and the wall on the floor of her cell, gasping for breath but not speaking.
Another 10 minutes pass before the guards enter her cell and cut the cloth from around her neck, after which they leave the cell and continue to watch outside the door.
Smith doesn’t move, and after a few more minutes, the guards enter the cell and try to rouse her by slapping her on the back, without any response.
The guards begin to perform CPR, though one of them is heard swearing that she hasn’t had any CPR training in 11 years.
A nurse arrives and an ambulance is called as the guards continue to perform CPR until the emergency workers arrive. They work on Smith for another 30 minutes, before she is put on a gurney and wheeled out of prison to the hospital.
Under questioning on Monday, Burnett acknowledged that “in a perfect world,” he would have entered the cell to save Smith.
Burnett was a fill-in guard who had just completed a night shift and was about to leaving for home when an "all call" sounded, indicating an emergency. He turned and went to respond, and found a video camera thrust into his hands.
Outside court, Smith family lawyer Julian Falconer said he had little sympathy for the guards who failed to save the teen's life.
"Human beings are human beings; good people do bad things," Falconer said.
"On that day, a group of guards did bad things."
After Burnett stepped down as witness, jurors were given a copy of the correctional investigator's report, which is highly critical of Smith's treatment.