A House of Commons security officer who was shot in the leg when a gunman stormed Parliament Hill says he thought he would die that day.

Const. Samearn Son was one of 20 parliamentary security officers and Mounties honoured Monday at RCMP headquarters for their bravery on Oct. 22 of last year.

In his first public account of the dramatic events, Son said he caught sight of rifle-toting Michael Zehaf Bibeau — who had just shot and killed a sentry at the National War Memorial — through the glass of the Centre Block doors.

Son instinctively reached for his pistol, which he only wore as a concealed weapon when working plainclothes duty. But that day he was in uniform inside Parliament's main building and did not have a sidearm.

Son decided to "square up" and try to block Zehaf Bibeau from shooting fellow officers inside.

"I could die running or I could die buying my partners some time," he said Monday following the emotional ceremony.

'I thought it was lights out'

Son believes his life may have been saved by the heavy west door under the Peace Tower that Zehaf Bibeau had to pull open, which meant the attacker's rifle was facing down.

The officer says he yelled "Gun! Gun! Gun!" before lunging and hearing a bang as Zehaf Bibeau fired his Winchester.

"I thought it was lights out," said Son, 38, who was born in a refugee camp in Thailand and came to Canada as a young boy. "I was super-grateful that I was still standing on my two feet."

The gunman continued up the stairs toward the Hall of Honour and only later did Son roll up his pant leg and notice a hole in his sock.

"I saw blood on my boots," said Son, who recovered after two months of rehabilitation.

Colleague won't go back to work

Fellow House of Commons officer Const. Charles Thom was at the top of the stairs, working plainclothes protective duty for Stephen Harper, prime minister at the time, who was attending party caucus.

Thom says he heard Son's shouts, turned to his left and shot Zehaf Bibeau once in the chest, only to see him continue running down the hall, much to the officer's amazement.

"I was very surprised," said Thom, 49.

He subsequently heard reports — which turned out to be false — of 13 more attackers on the roof of the Centre Block, a terrorist at the parliamentary visitors' centre and a sniper atop the Langevin Block across the street.

"So we had to be prepared for everything."

Thom has been diagnosed with post-traumatic stress disorder and has not returned to his job, nor does he expect to.

"I have zero interest in going back to work," he said. "It's not very fun. You get these fog-like episodes, a lot of anger.

The attack on Parliament Hill actually lasted only 90 seconds for Thom, but he says it seemed like a lifetime.

"It was a day from hell, Oct. 22."