Interesting points of view, I wonder however why that person has stopped at the lights in such a position that they had to move over if an emergency vehicle should appear. Why hadn't they considered this when stopping, does no-one plan ahead any more?
As for legality, I wouldn't care if I got a ticket, someones life could be on the line. If you have a dashcam (who hasn't these days) it should be easy to argue the case.