The gunman entered the Canadian Parliament buildings through the Centre Block just under the Peace Tower and shot a security guard in the leg. There were then around 20 and 30 gunshots exchanged between the gunman and security. The gunman ran down the Hall of Honor to the entrance of the Library, which is beside the office of Kevin Vickers, the Sergeant-at-Arms of the Canadian House of Commons. Vickers grabbed his handgun and went into the hall. He dropped to the ground and shot three times. The gunman was engaged by six officers. One of the shots fired by Constable Curtis Barrett hit the gunman in the head and killed him. 