HALIFAX -- Nova Scotia's top court focused on the potential future danger posed by an American woman who plotted a Valentine's Day shooting spree at a Halifax mall as she appealed her life sentence Tuesday.

Three members of the Nova Scotia Court of Appeal heard arguments Tuesday in an appeal of Lindsay Souvannarath's sentence of life with no chance of parole for 10 years.

Souvannarath, 26, pleaded guilty to conspiracy to commit murder in a 2015 plot to shoot people at the Halifax Shopping Centre, but is asking the appeal court for a fixed term of 12 to 14 years.

She argues the sentencing judge mistakenly imposed a burden on her to prove she was remorseful and had renounced anti-social beliefs.

But at the appeal hearing Tuesday, Justice Anne Derrick wondered whether "future dangerousness" was one of the sentencing judge's main considerations.

"When I read his decision I didn't see him treating remorse as an aggravating factor," said Derrick. "I saw him taking remorse into account in assessing what sentence he should impose in light of him not being satisfied that he could be confident she wasn't going to be an ongoing danger."

Defence lawyer Peter Planetta told court he believed that was a consideration in light of a previous Supreme Court of Canada decision related to an Ontario terrorism case, but he said the previous case involved "hardened terrorists" and added that Souvannarath's case "pales in comparison."

"In this case it escalated or raised the sentencing bar too much," Planetta said.

Derrick returned to the theme later in the hearing.

"Isn't it dangerousness that the trial judge was trying to address . . . not on the issue of remorse or not, but is she dangerous?"

Replied Planetta: "Yes, and I would submit rely heavily on the lack of remorse to determine that issue."

Justice Jamie Saunders noted the court has four volumes of appeal books containing the record of Souvannarath's transmissions on the Internet. He said she was also aware that her two cohorts had filmed the mall's food court to determine the best location for the attack.

"She speaks glowingly, that's my adjective, about the carnage she hoped to inflict and the pain and the suffering," said Saunders. "So I'm wondering where else could Justice (Peter) Rosinski go for guidance in those circumstances than to consider the terrorism cases?"

"It's still not a terrorism offence, that's not what she's been charged with," Planetta replied.

Outside court, Planetta told reporters he believes the issue of whether his client is an ongoing danger to the community will play a role in the appeal decision.

"It's one of the issues that their decision is going to come down to -- how much of a factor it is and how much it should influence the sentence," he said.

Crown lawyer Tim O'Leary told the court he believes the sentence was appropriate, though it was on the top end of what's recommended for the offence.

"I don't mean to sound trite but sometimes the facts really do speak for themselves," said O'Leary.

He said he believes the trial judge did not commit any legal errors in his decision given the evidence before him indicated that the planned attack was imminent had arrests not been made.

"The intention was to inflict as many casualties as ammo allowed," he said. "Really a life sentence by its very nature would be rare, but this is the rare case that warranted a life sentence."

The three-judge panel reserved its decision.

Souvannarath was not in court Tuesday.

She pleaded guilty in April 2017, about six months after Randall Shepherd -- a Halifax man described in court as the "cheerleader" of the foiled plot -- was sentenced to a decade in jail.

A third alleged conspirator, 19-year-old James Gamble, was found dead in his Halifax-area home a day before the planned attack.

Planetta brought up the issue of sentencing parity, pointing out that her sentence was more than that handed to Shepherd.

The origin of the conspiracy was traced back to December 2014, when Souvannarath and Gamble began an online relationship.