"When a man, even with the best intentions, breaks the moral laws we live by, we really don't need man-made laws to punish him."
I hate to saddle the only female director in the film noir universe with the "sensitive" descriptor, but it's one of the first words that come to mind when considering this. Lupino has such sincere empathy for all of these characters, and this has to be one of the most dramatically ambitious movies of the studio era for the way it sets up a situation for which no emotionally satisfactory resolution is possible, then follows it to the bitter, unsatisfying end.
In its own way, this is almost as tense and suspenseful as The Hitch-Hiker.