TORONTO -- A teenage inmate's already disruptive behaviour took a drastic turn for the worse after she witnessed a hostage taking, an inquest into her death heard Monday.

Alfred Legere, former warden of the Nova Institution for Women, said he even felt compelled for the first time to have Ashley Smith placed in a special restraint chair.

"I thought she was going to kill herself by banging her head on the floor," Legere testified. "There was blood."

The hostage taking occurred Aug. 17, 2007, when "Inmate A" -- who had taken hostages four times previously -- used a metal part from a cassette deck to threaten a guard on Nova's segregation range.

While the situation was resolved, Smith began acting out immediately afterward, Legere said.

The incident also had a devastating effect on an already strapped facility. Thirteen out of 85 staff filed for workers compensation. It also permanently changed Nova's "therapeutic" environment, Legere said.

Within weeks, Smith was moved to Grand Valley Institution in Kitchener, Ont., to allow Nova to recruit more guards.

"We were incapacitated as far as staffing goes," Legere said.

The hostage taking occurred during Smith's second stay at Nova, an 80-inmate prison in Truro, N.S.

It was the first adult prison in which Smith, then 18 years old, would be incarcerated following almost three years at a youth detention centre in New Brunswick and her self-harming reputation preceded her.

Unusually, she was placed in segregation on arrival Oct. 31, 2006, and began causing problems almost immediately.

Among other things, Smith smeared herself with excrement and threw feces at guards. She trashed two segregation cells by breaking sprinkler heads and windows and damaging cameras.

Emergency response teams intervened. They used a noxious spray to control her.

"Here we go," one staff member wrote in a memo. "Two days here and she is performing true to form."

Legere admitted he underestimated just how challenging Smith would be.

"I'd never seen such an ingenious manipulator of her cell effects in order to cause havoc," he said.

Front-line correctional officers, citing health and safety concerns, refused to watch her, forcing managers to step in.

"They were very upset about this and how we were going to handle it," he said of the guards.

Staff built a platform with a step ladder outside so they could observe Smith from the back window of her cell.

When it proved to be too cold, they built a shelter around the platform and put a heater inside.

At another point, the facility put in a specialized window into her cell door that could be relatively easily replaced if she covered it.

"She was creating significant operational issues," Legere said. "She was taking up a lot of our resources. I didn't see that she was getting any better."

Regular reviews of her segregation status resulted in the decision to keep her there, both for her own safety and that of others. The result was that Smith spent her entire Nova stays in isolation.

Prison authorities, among them mental-health professionals, drew up a plan that included withdrawing warmth and giving her the silent treatment if she acted out.

Ultimately, the decision was made to move her to the Regional Psychiatric Centre in Saskatoon -- to put her in the "treatment environment she needs," the inquest heard.

Before Smith would return to Nova, the facility requested another $88,242 from Ottawa for extra resources to help deal with her.

"Instead of shipping her to get respite, we need to have resources here," the request read.

Legere said he got partial funding.

Smith returned to Nova on July 26, 2007, and was placed back in segregation.

Legere called Smith "very intelligent but very immature."

"She surprised me sometimes about how little she knew about worldly things," he said.

Asked if there were triggers to Smith's outbursts, Legere said: "No. Indeed, they puzzled me."

He testified he became apprehensive about the notion of ignoring Smith's self-harming behaviours as a way of discouraging them. He said he reminded correctional officers that their first obligation was to preserve life.

Smith choked herself to death Oct. 19, 2007, at Grand Valley.