Here's the rules from the Highway Traffic Act
Basically, it just says you have to yield to the pedestrian, so once the pedestrian is clear, you may proceed with caution.
It also indicates it is NOT acceptable for a pedestrian to push the button and then walk out into traffic...that they must be sure the vehicles are yielding before proceeding into the roadway!!!
Pedestrian corridor, duties of driver
141(1) Subject to subsection (2), where
(a) a pedestrian is at
(i) the kerb or edge of a roadway, or
(ii) a place of safety,
that is adjacent to a pedestrian corridor that lies across a roadway upon which a vehicle is approaching so closely to the pedestrian corridor as to endanger the pedestrian if he were to enter it; and
(b) the pedestrian
(i) is intending to cross the roadway in the pedestrian corridor, and
(ii) is giving notice of his intention by extending his hand and arm at full length in such a manner to indicate clearly the direction in which he intends to cross, the driver of the vehicle shall yield the right-of-way to the pedestrian by slowing down or stopping if necessary.
When vehicle stopped at pedestrian corridor
141(2) When a vehicle is stopped at a pedestrian corridor, the driver of any other
vehicle overtaking the stopped vehicle shall bring the vehicle to a full stop before entering the pedestrian corridor, and shall yield the right-of-way to a pedestrian,
(a) who is within the pedestrian corridor upon the half of the roadway upon which the vehicle is stopped; or
(b) who is within the pedestrian corridor and is approaching that half of the roadway from the other half of the roadway so closely to the vehicle that he is in danger if the vehicle were to proceed.
Passing vehicles in vicinity of pedestrian corridor
141(3) When a vehicle is approaching a pedestrian corridor and is slowing down for
the purpose of yielding the right-of-way to a pedestrian, the driver of any other vehicle approaching from the rear shall not overtake and pass the vehicle first mentioned.
Duties of pedestrian
141(4) No pedestrian shall leave the kerb or other place of safety at a pedestrian corridor and walk or run into the path of a vehicle that is so close that it is impracticable for the driver of the vehicle to yield the right-of-way.