The way I see it there were three possible reasons for why:
(1) The guy didn't notice the big ambulance with flashing lights and sirens;
(2) The guy did notice it but chose maliciously not to get out of the way;
(3) The guy did notice but didn't want to go through the red-light-camera and have to somehow convince the powers that be that he did it for a good reason.
I know what I think is most likely.