Standard practice is to have the extinguisher in the vicinity in case something does happen.
If the fire cannot be completely extinguished with one extinguisher, leave the area, use a pull station to call the Toronto Fire Department or call 8-2222. Do not use elevators. If a fire warden tells you to leave the building, do so immediately. The building will be evacuated by activating the fire alarm or by fire wardens in the event of a power failure. If possible arrange for attending emergency personnel to be met in the vicinity of the elevators on the first floor.