A police officer broke down in tears as she said she was "not a trigger-happy officer" and only fired her Taser at a 92-year-old amputee to protect him from being struck again with a baton by her colleague.
Pc Rachel Comotto said she believed using the Taser was the safest way to "protect" Donald Burgess, a single-leg amputee and wheelchair-user who already had been pepper sprayed and hit with a baton.
Police had been called to Park Beck care home in St Leonards-on-Sea, East Sussex, after Mr Burgess had reportedly threatened staff with a serrated knife that he used to eat his lunch.
Comotto, 36, denies one count of assault occasioning actual bodily harm for use of the Taser.
Her colleague, Pc Stephen Smith, 51, denies two counts, one relating to his use of Pava spray and another for using a baton during the incident, on June 21 2022, at Park Beck care home.
Southwark Crown Court has heard that Mr Burgess, who had diabetes and was being treated for a urinary tract infection, was tasered, hit with a baton and sprayed with Pava within 83 seconds of the officers entering his room.
Mr Burgess was taken to hospital after the incident, and later contracted Covid. He died 22 days later aged 93.
Giving evidence on Friday, Comotto told jurors: "I honestly believed the Taser was necessary.
"It was proportionate because other tactics had failed. If I didn't act, something worse could happen."
She said Mr Burgess had not dropped the knife, despite being sprayed and struck, and she feared a second baton blow from her colleague would cause more harm.
"I saw Pc Smith raise his baton up and I believed at that point he was going to strike Mr Burgess with his baton," she said.
Asked why she used her Taser at that moment, she said: "To protect Mr Burgess - to resolve the situation safely and quickly."
Prosecutor Paul Jarvis KC asked: "If you were worried about officer Smith hitting him with the baton, why wasn't telling him to stop a better option?"
"In hindsight, with all the information I have now," Comotto said.
"It's not rocket science, is it?" Mr Jarvis said. "Why taser someone to stop a baton strike instead of just saying 'Steve, stop'?"
"I don't control my colleague," Comotto said. "I don't know if he would have heard me; he was focused."
Mr Jarvis said: "The idea that it was to protect you or your colleague was to defend the inexcusable," as Comotto began to cry in the witness box.
Jurors were shown body-worn video which appeared to show Mr Burgess lowering a knife after being sprayed, and only raising it again when the baton was brought out.
"It looks like he's trying to fend off the baton blow, not waving it around wildly," Mr Jarvis said.
"It's been three years. I can't remember how I perceived it at the time," Comotto replied.
"You've done pretty well so far," Mr Jarvis said. "I'm just asking you to help us with this bit."
He asked: "And you believed the best way to protect him was to taser him?"
The court was told Comotto did not speak to Mr Burgess before firing, or explain what a Taser was, despite believing he had dementia and being aware he was in a wheelchair, with one leg.
"Did you once ask him how he was?" Jarvis asked.
"No,"Comotto replied.
"Do you think he might have been afraid?"
"Potentially,"she said.
Jarvis then read from the use-of-force form Comotto completed after the incident, highlighting that she had ticked every box on the list, including protection of self, protection of the public, prevention of offence and prevention of escape.
"Where did you think Mr Burgess was going to escape to?" he asked.
"The only route was through the door,"Comotto said.
"You're telling us if you didn't fire the Taser, he was going to make a break for it?"
"There was potential for it,"she said.
"Did you tick every box on that form to give yourself every possible justification?"Mr Jarvis asked."Was this the kitchen sink approach?"
Comotto denied it,saying she believed her actions were necessary based on the information she had at the time.
Mr Jarvis pointed out that the officers had been in the room for just one minute and 23 seconds before the Taser was fired.
"It felt like a lifetime,"Comotto replied.
"I'm not a trigger-happy officer,"she added."It's the first time I've fired my Taser."
The trial continues.