An intramuscular injection should never be done in the neck as it can perforate a major vein, a carotid artery, the trachea (windpipe) or esophagus (food pipe) but rather in the deltoid (shoulder) or the gluteal muscles (buttocks) or quadriceps (thigh muscles).
Miami is six feet above sea level today. New Orleans is 1 to 2 feet below. If Miami was flooded, New Orleans would be too.
Science has shown us that 'memory' is somewhat unreliable and that people can remember seeing things that just weren't there, or forgetting things that were there. The film's thesis that people retain in memory everything they have ever seen, like a video camera, is not supported by facts.
Narration early in the film indicates that Miami's temperature is so oppressive that everyone works at night and stays indoors in the daytime. Shortly after, Bannister finds Mae outside, in the daytime on a rooftop oasis, where it appears quite pleasant and neither character looks uncomfortable or even warm.
Much of the plot centers around Bannister observing 3D projections of people's memories, even noting things that the person could not have seen and therefore not remembered. The projections of a memory would be from the person's perspective.
Nick Bannister is a war veteran and seasoned private investigator, he is not the sort of person who would stumble awkwardly through clotheslines full of washing when pursuing a dangerous man, he would apply common sense and simply walk around the washing lines.
Nick Bannister is supposedly an expert at getting into people's memories; he would not spend 12 hours at the Police station in fruitless suggestion trying to access Falk's memory when he already knows the best way to access the memories of a dying person is to suggest a memory of an enjoyable event; which he later does, with immediate success.