RCMP Const. Kwesi Millington denies he panicked when he confronted Dziekanski at Vancouver's airport in October 2007. (CBC)

The RCMP officer who shocked Robert Dziekanski several times with a Taser is denying allegations that he had panicked or tried to cover up his actions.

Const. Kwesi Millington, 32, was under intense grilling Tuesday at the Braidwood public inquiry by Walter Kosteckyj, the lawyer representing Dziekanski's mother.

Millington denied he panicked when he confronted Dziekanski at Vancouver International airport in October 2007, and insisted that his initial accounts were his best memory — even though parts of those accounts were wrong.

Kosteckyj questioned the officer about his RCMP training and the policy on the use of Taser stun guns.

Millington admitted he knew the stun gun would keep firing when he pressed his finger on the trigger, and he did so while knowing that sustained multiple deployments were to be avoided, the inquiry heard.

Robert Dziekanski was jolted up to five times with a Taser by the RCMP at the international arrivals area of Vancouver International Airport. (Paul Pritchard)

He also admitted he did not give the required Taser warning, nor did he give the stricken Polish immigrant medical aid or remove the Taser probes as required, the inquiry heard.

"You panicked over the entire situation," Kosteckyj suggested to Millington.

"No, I didn't," the officer replied. "I feared for the safety of the other officers and so I acted to stop the threat."

Millington fired the Taser after Dziekanski picked up a stapler and continued to stun him even though Dziekanski had fallen to the floor, writhing and screaming, the inquiry heard.

The officer's initial accounts of what happened contained numerous inaccuracies, several of which suggested Dziekanski was more aggressive than what's shown on a bystander's video.

Kosteckyj suggested Millington was covering up his action in the incident because he panicked at the airport. The lawyer also said Millington never made any efforts to correct or clarify his many errors in his notes and statements.

No time for warning: officer

Consuming glass after glass of water in the witness chair, Millington, who fired the Taser within seconds of arriving, insisted he never had time to warn Dziekanski before the weapon was used.

"You couldn't see why you should take the time to give a warning?" Kosteckyj asked.

"I didn't believe there was time," Millington replied.

Millington added that the other three officers at the scene knew Dziekanski had been stunned and could have told firefighters and paramedics. However, at least two of the officers thought Dziekanski had only been stunned twice.

"You just abdicated all responsibility for the use of the Taser that night to others, didn't you?" Kosteckyj said. "You just assumed others were doing it."

"I knew they were capable of giving the same information I could, with the exception of the four deployments," Millington said.

Crown prosecutors decided last year not to charge Millington, Const. Gerry Rundel, Const. Bill Bentley and Cpl. Benjamin Robinson, saying they acted with reasonable force.

Rundel and Bentley have already given their testimony at the inquiry. Robinson will testify after Millington.

Thomas Braidwood, the inquiry commissioner, could make findings of misconduct against the officers or anyone else involved.

With files from the Canadian Press