The Toronto police officer who fired the fatal shots that killed Reyal Jardine-Douglas told a coroner’s inquest Thursday he felt cornered and had no choice but to shoot the emotionally disturbed man three years ago.

"I'm stuck in a situation where I feel I'm about to die," Const. Kyle Patterson told the jury, when recalling the events of Aug. 29, 2010.

Paterson was responding to a 911 call that indicated Jardine-Douglas, a 25-year-old man suffering from an undiagnosed mental illness, had boarded a bus and was possibly emotionally disturbed. The officer testified his goal was to assess him and possibly get him to a hospital or apprehend him under the Mental Health Act.

Mentally Ill Inquest 20131024

Police Const. Ehsan Haghshenas (right) leaves coroner's court with lawyer Gary Clewley in Toronto on Thursday, Oct. 24, 2013. Haghshenas's partner shot the mentally-disturbed man Reyal Jardine-Douglas, 25, in Toronto in August 2010. (The Canadian Press)

The inquest heard audio from police dispatch that day. The dispatcher tells officers that Jardine-Douglas had been extremely agitated lately and wasn’t on any medication.

The dispatcher also passes on a warning from Jardine-Douglas’s sister who called 911 initially: "[The] complainant is advising to use caution, says he's very unpredictable and very agitated and paranoid. Doesn't think he's carrying any weapons but she's worried he may have something on him unknown."

"The plan essentially that I had was to locate this male and speak to him in private," Paterson said.

But he testified that the plan quickly changed when he boarded the bus and Jardine-Douglas moved towards him with a knife.

'It was scary'

Paterson says he initially told Jardine-Douglas to come with him in a calm voice, then commanded him to drop the knife. But the officer said he never got a response.

Paterson said he backed off the bus and kept backing off, with Jardine-Douglas getting off the bus and quickly moving towards him.

Reyal Jardine-Douglas seen on TTC bus prior to shooting

Reyal Jardine-Douglas had boarded a bus, where his interaction with Toronto police began on August 29, 2010. (Handout)

"It was scary, his eyes were literally focused on me and me only, like a stare, like a challenge," Paterson said.

Outside the bus, Paterson says he backed into a pole, then a fence and was cornered with nowhere to go. That’s when he fired three shots. One struck Jardine-Douglas. The fourth and fatal shot came as the 25-year-old tried to get back up.

"For the sake of myself, my partner and everyone in that general area, I made the conscious decision to discharge my firearm," Paterson said.

Earlier in the day, the other officer at the scene, Const. Ehsan Haghshenas told the inquest that Paterson had no choice but to shoot the emotionally disturbed man.

"He was gonna kill my partner," Haghshenas said.

Haghshenas testified that when he reached the bus, Paterson had already boarded, asking Jardine-Douglas to drop the knife.

Haghshenas testified that Jardine-Douglas immediately came towards the officers with a ceramic knife in his hand forcing them off the bus and that’s when they drew their weapons.

Haghshenas testified that Jardine-Douglas first turned to the back of the bus where he had gone, but then moved in the opposite direction, towards Paterson.

"At that point [Jardine-Douglas] didn’t have any emotion on his face, he just looked at me distinctively and then turned his whole attention to Constable Paterson," Haghshenas said.

 Events unfolded quickly

 From there Haghshenas said events transpired quickly.

"You gotta understand the whole situation in my mind played out for 10 minutes, [but] in reality wasn’t even 10 seconds," he said.

Toronto police constables Kyle Paterson and Ehsan Haghshenas

Toronto police Const. Kyle Paterson, seen on the left, was the first to enter the TTC bus that Reyal Jardine-Douglas was riding on. Const. Ehsan Haghshenas, at right, followed his partner onto the bus on Aug. 29, 2010. (Handout)

Haghshenas said he thought about firing his own weapon at Jardine-Douglas "because he seemed like he had a mission and wanted to kill Constable Paterson."

The officer, with 20 of months experience at the time of the call, said Jardine-Douglas had options to get away from police after he left the bus, but chose to go after Paterson.

Despite repeated commands to drop the knife, Haghshenas said that Jardine-Douglas never responded and never hesitated to suggest he even understood the orders from police.

When asked by the lawyer for the Jardine-Douglas family, John Weingust, why officers didn’t try a softer approach, to calm the victim down, Haghshenas said there was no time and that their training teaches them to handle the situation, not the individual.

"I have to protect my own life, my partner’s life and whoever is around there," he said, describing facing a suspect approaching them with a knife.

"Me standing there saying: ‘Come on, let’s calm down,’ is gonna get me stabbed," Haghshenas said.

The inquest is examining the deaths of three people who were shot dead by Toronto police in separate incidents in 2010, 2011 and 2012. All three of the deceased had mental-health issues and each were holding sharp items when they were shot.