Factual error: Right before Frank humiliates Dorothy for the first time, he blows out one of the gaslights in her apartment. That is never done in real life, for the same reason you would not blow out the pilot in your stove.
Visible crew/equipment: When Frank humiliates Dorothy and Jeffrey watches from inside the closet, you can see someone walking out of the bathroom. This happens right after Frank leaves and before Jeffrey steps out of the closet.
Question: When Jeffrey and Sandy are discussing where Isabella Rossellini lived, it is mentioned that she lived on the 7th floor of the apartment building. When they show the outside of the building it appears to have only 4 floors. Was this symbolic or an oversight?