Because of its (long) length, it could have cornered me into a fatal situation.
Agreed that the bus driver should have paid attention to any traffic ahead of him (incl. you) and have kept a safe clearance.
Was the pedestrian 'WALK' signal on the crosswalk to your left or to your right (or both)? If there was only a crosswalk to your left then it's possible that the bus had a green right-turn arrow at the same time that you saw the ped. WALK sign. But if there was a WALK sign to your right and/or you had a green light then the bus must have made a quick start after a right-on-red after stop or he ran the red without coming to a stop first. In either case he shouldn't have crowded you.
But I disagree a bit about your concern above. Unless the bus was wider at the rear than at the front (not at all common), then it wasn't really in a position to corner you. The moment you felt the bus was getting too close you had the option to slow down and stop. Once you're stopped the bus can't move its rear end over toward you without steering the front end to the left and hitting the storage container.