CAUTION: This story contains graphic details.

TORONTO -- A psychiatrist, who works with some of the most dangerous prisoners in the country, teared up Tuesday as she testified about watching video of prison staff injecting a troubled inmate with medication over her objections.

Dr. Michelle Roy told the Ashley Smith inquest that she was dismayed to discover only recently a "more than huge" discrepancy between what a nurse had described by phone about the teen's state and the reality of the situation.

"It is still disturbing for me," Roy said.

"The situation that was described to me was a very severe agitation, that her life was in danger."

In fact, the inquest has seen -- in the video Roy viewed three weeks ago for the first time -- Smith was not out of control at the prison in Joliette, Que., when she prescribed a powerful tranquilizer for Smith over the telephone.

Prison staff, Roy suggested, had completely misled her.

"The only explanation I have is they were not used to dealing with this kind of patient," Roy said.

Prescribing by phone was a perfectly normal practice that relied heavily on the prison nurse to convey accurate information, said Roy.

"The nurse would give me the clinical picture of a patient who would need emergency treatment," she said.

"The nurse is on site. She has to assess the patient. It's the nurse's job to do that."

CAUTION: THIS STORY HAS GRAPHIC CONTENT.

On a particularly harrowing day in July 2007, a nurse at Joliette Institution for Women called Roy to describe "a very problematic situation."

The teenager, who had a propensity to self-harm and whose mental health had been deteriorating after years in segregation and multiple prison transfers, was apparently in a severely agitated state.

"It was a very dramatic situation," Roy testified.

"She had objects in her vagina. She was bleeding. There was a possibility of electrocution."

Roy advised the nurse to put Smith in four-point restraints, prescribed a powerful tranquilizer, and recommended a transfer to the general hospital for an internal exam.

"My expectation when I gave those orders was to inform security that this patient must be put on restraints immediately, and then offer her medication," Roy said.

"The most important thing was to calm her down."

Roy said no one ever informed her in subsequent calls that Smith had been injected over her objections.

Various nurses would call to say Smith was still extremely agitated -- something not reflected in the prison video that shows the teen at times bantering and joking with staff.

"The description at that time was very dramatic," Roy said. "I was assuming that she was out of control."

Over a period of about 10 hours, the psychiatrist ended up prescribing five sets of injections for the physically restrained teen -- believing the inmate was accepting them voluntarily.

Roy, who is currently doing a Masters in bioethics, said the only time she prescribed medicating Smith involuntarily was for a transfer flight, but even then only if the inmate was out of control.

However, the inquest has seen video of prison staff waking Smith, then telling her she had no choice but to accept the drugs even though she was obviously calm and compliant.

One of the nurses involved at the time, Melanie Boucher, has previously testified that she accurately described Smith's situation, but Roy disagreed with that view.

Roy never met or assessed Smith, who was moved to Joliette for a month in July 2007. All she received was a small medical file that contained "very little information."

She recommended improved communications among psychiatrists and prison staff, as well as regular meetings with other psychiatrists working in corrections to share experiences and best practices.

Smith, of Moncton, N.B., was 19 when she choked herself to death in her segregation cell in Kitchener, Ont., in October 2007.