Kevin Vickers is Sergeant-at-Arms of Canada's Parliament. He is charge of security at the Parliament Buildings. Usually, he doesn't have to defend them himself. Yesterday was different. Vickers shot and killed a gunman who came into the buildings.
This video shows what happened when Vickers went into work today.
As Vickers walks down the hall, he is carrying a mace, a medieval weapon. It's a symbol of Parliament's authority.
The song everyone sings at the end is Canada's national anthem. They sing it partly in English and partly in French.