If you loved Fail Safe, try The Hill
A bridge between a film you've already seen and one most people haven't. Here's what they share, and what the second one does that the first one doesn't.
What they share
Both films are directed by Sidney Lumet, and they both carry the dread mood tag, and they sit in Drama / War territory. If that's the register that drew you to Fail Safe, the second film will land in a comparable space — through a different lens.
dread
What The Hill is
You're a British prisoner in a North African stockade during World War II. Days melt into lockstep drills under a blazing sun. But a new sergeant arrives, one who questions the camp's methods. Lumet's stark vision implicates the whole theater of war. It lingers.

