All the events in this film are supposed to have occurred in a period of one hour, from 11am until noon. But this would have been impossible in real life; there were simply too many things going for them to have taken place in just an hour. A two or three hour time span would have been more realistic.
None of the weapons used in the film recoil when fired. This, of course, is due to blanks being used. However, for better realism the actors should have been instructed to simulate recoil by momentarily snapping their wrists upward as each shot is fired.