Sahar Bahadi, the mother of Sammy Yatim, in Toronto in January. (Photo by Chris Young/The Canadian Press)

A blunt exchange on what her son's life could've been had he survived a fatal shooting by a police officer was too much for a mother, who walked out of the cop's sentencing hearing, hysterical.

It's been a long, emotionally draining journey for Sahar Bahadi, whose son Sammy Yatim was killed by Toronto police officer James Forcillo on an empty streetcar in the summer of 2013.

Following a lengthy trial, Forcillo was found not guilty for second-degree murder but guilty of attempted murder in January. He had fired two volleys of shots at the knife-wielding teenager, who refused to obey his commands to drop the knife. Yatim sustained fatal injuries during the first volley of shots, but the second volley is the one for which Forcillo was convicted.

On Wednesday, a hearing to determine what punishment fits the crime kicked off in a downtown Toronto courthouse.

The Crown prosecution is seeking an eight-to-10-year sentence. Defense lawyer Peter Brauti, on the other hand, argued that imprisonment in this case would "serve no real purpose other than denunciation," and is asking for a sentence of two years less a day, to be served in the community — meaning Forcillo wouldn't see jail time.

The defense is also expected to challenge the mandatory four or five-year minimum sentence for attempted murder and argue that the relevant sections in the Criminal Code are unconstitutional.

Presenting what the judge should accept as facts that led to Forcillo being found guilty, Brauti was met with resistance from Justice Edward Then, who took issue with, among other things, what he saw as Brauti asking him to take Forcillo's version of events as fact.

The morning took an emotional turn during one exchange between Brauti and Then, which resulted in Yatim's mother walking out in tears.

Towards the end of his submission on the facts, Brauti argued that because the first volley of shots left Yatim paralyzed, he wouldn't have felt any discomfort from the second volley — the one for which he was found guilty.

"Are you suggesting that I should look at the bullet wounds as inconsequential?" asked Then.

"From an actual harm perspective, we know that [the second volley] doesn't cause death, accelerate the death, affect his health or cause discomfort," Brauti responded.

"It's not as if no harm had happened," said Then, who appeared bewildered and irritated at many points throughout the defense's submissions. "There was substantial harm to Sammy Yatim. The only wrinkle is by the grace of God he had been rendered a quadriplegic by the preceding bullets."

'This is as low harm as it gets, other than the bullets missing him.'

"This is as low harm as it gets, other than the bullets missing him," said Brauti, adding that while a quadriplegic lives with serious trauma, Yatim was able to avoid that.

It was at this point that Bahadi walked out, accompanied by a victim's services staff member, breaking into audible cries as she got to the door. The cries turned to screams, that could be heard from inside the courtroom for several minutes.

Bahadi was sitting on a chair, being comforted by staff when court broke for recess. She returned after break, eyes red, taking her seat in the gallery.

The defense is now making submissions on the constitutionality of mandatory minimums.

Judge Then said he will reserve his decision.