I cannot remember much about this movie,

I know it was set during World War 2, at the end of the movie two either american or english spies were trapped in an underground room of possibly a bank or train station, and the nazis had them surrounded, they pumped water into the room to either drown them or get them to surrender, the two spies put a gun to each others heads and counted to 3 and killed each other.

Thanks

Operation: Daybreak

That's it, as soon as I saw Martin Shaw's name on IMDB more memories of it came back, thanks again