Originally called the "Central Emergency Government Headquarters" and (poorly) explained during construction as an "army signals" base. Oddly enough, the bunker did have sophisticated communications installed, including a full CBC radio studio. The bunker served as an army communications hub until it was deactivated in 1994.
In addition to the points mentioned above, the bunker is wrapped in a thick pad of gravel to further cushion against shock.
The bunker has been designated a "National Historic Site" by the Historic Sites and Monument Board of Canada.