Kevin Vickers said he was in tears the morning after the shooting of Michael Zihaf Bibeau on Oct. 22.
"That day was a blur to me," he told students at Mount Allison University in Sackville, N.B.
"I went home that night and I had a hard time going to sleep and I woke up at around 5:30 in the morning and I was crying. It was the loneliest moment of my life."
Vickers, who was the House of Commons sergeant-at-arms at the time, has been credited with firing the shots that killed Bibeau. Soon after the shooting, Vickers was appointed Canada's ambassador to Ireland.
On the day of the shooting, Vickers said he "bumped up against a moment in history" as he recounted what went through his mind in the Centre Block of the Parliament Buildings.
"I found myself on one side of the pillar and a gunman on the other side of the pillar," he said.
"There was a moment where I thought I'd just reach out and grab the gun. He shot and fired. And the moment he shot and fired, I dove through the air, landing on the floor just beneath him."
Vickers is an Irish-Canadian from New Brunswick who had a lengthy career in the RCMP before joining the House of Commons security staff in 2005 and becoming sergeant-at-arms in 2006.
After the shootings, Vickers said his mother called him on four straight days suggesting he come home to New Brunswick to see his family. It was then he realized she knew he needed to come home for his own state of mind.
He reflected on the importance of mothers based on that experience, and how he felt when he got back to New Brunswick.
"I was OK now, and it was all thanks to mom," he said.
Vickers said he prayed for Bibeau, who stormed into the Centre Block after killing a soldier at the National War Memorial in Ottawa.
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