Occurrence at owl Creek is an old short story by Ambrose Bierce. It’s been adapted to screen many times and, of course, many variations (rip-offs, if you will) exist. The original took place in the US during the Civil War, which obviously isn’t Budapest, but otherwise the description sounds exactly like Occurance at Owl Creek. So, possibly what you saw is a foreign variant retelling of Occurance at Owl Creek? I’m definitely interested in hearing any kind of resolution you get here. If you find the name from another source please share it back here.