Prime Minister Stephen Harper disappeared into a caucus room closet during the Parliament Hill attack on Oct. 22 in order to ensure Canada had a functioning government in the event of a catastrophic attack.

In a year-end interview with the CBC's chief correspondent, Peter Mansbridge, the prime minister revealed for the first time how he coped inside that room as Michael Zehaf-Bibeau stormed Centre Block after killing Cpl. Nathan Cirillo.

​Harper said he took evasive action based on the regular training he receives from the RCMP, and that the first person he called after the tragic events were over was his mother: "I just wanted to assure her I was OK, and I could tell by her voice that she was concerned."

Harper said there was concern in the caucus room because no one knew what was unfolding outside the closed doors.

"All you hear is a whole lot of shooting coming towards you, and you don't know if that's a firefight or whether it's just a bunch of guys with automatic weapons wiping everybody out in their path," Harper said.

Harper said while some of his colleagues feared for their lives, as prime minister he lived the experience a little differently.

"As prime minister I have access to obviously all the government's intelligence, all security risks that are faced by the country and by me personally, so you're in a different headspace than most people who are suddenly facing this situation for the first time," the prime minister said.

Harper would not say whether he was frightened by the incident, saying instead he doesn't like to talk about himself and that he has received "training" from the RCMP. He said the training consists primarily of drills that are meant to simulate this type of event.

Getting to safety

It is known Harper was put inside a storage closet in the caucus room for his own protection by some of his colleagues.

The prime minister would not comment on this, saying only that part of his role is to "extricate" himself from situations.

"One of the things you try and do is conceal yourself if you can, but obviously the best situation is to exit," Harper said, adding the goal is for the prime minister to be able to continue to run the government.

While Harper was quickly removed from Parliament Hill a "few minutes" after the all-clear had been declared by Sergeant-at-Arms Kevin Vickers, other MPs and employees were on lockdown for hours while police made sure the buildings were secure.

At a caucus meeting a week after the incident, Harper expressed remorse to his MPs about leaving them behind while he was escorted to safety.

Watch Peter Mansbridge's full interview with Stephen Harper tonight on The National, at 10 p.m. on CBC Television, on CBC News Network at 9 and 11 p.m. ET and on cbcnews.ca.