When Mike is done putting his scrap books items in a nice pile, the scissors keep changing positions as the scene progresses.
The same NYC Transit cop that helped MaryAnn on the platform is the same cop who brought her home in a patrol car. In those days the Transit Police would have had to hand her over to an NYPD Officer if she needed to be taken home in a patrol car as the Transit Cops in 1961 would not have been able to leave their posts and had no access to a patrol vehicle.
When Mike returns drunk the first time, Mary Ann gets up and turns on a single light dangling from a cord, but lights come on all over the apartment. It becomes especially bright in the kitchen area, for no apparent reason, where Mike is, away from where Mary Ann is.