Like several previous commentators I'd love this little gem to get an airing on TV. I saw it as a "supporting feature". In 1974 we were in the dying days of "double features" in the UK. I think the "main" feature that day was "Electra Glide in Blue". Anyway, I fondly recall this as a very effective thriller. It certainly conveyed claustrophobia and menace. It would be great to have an opportunity to re-appraise this film.