I found it really surprising that a film of that era was so blatantly homoerotic. Like you say, you have to respect his nerve.

I think that the one-set thing was really effective, too. For some reason, it just made the film so much more claustrophic and tense. When the sirens were screaming towards the end, I was filled with dread even though I had hoped the murderers would be caught throughout the film.

Definitely one of my favourite Hitchcock films.