The Long and the Short and the Tall (1961)

Powerful war drama.
This film is IMO, the greatest war film ever made, and maybe the greatest film.
Seven UK soldiers in WW2 find themselves in a predicament they didn't expect.
They were supposed to run a "test" so to speak, and not see real action. That's why four of the seven are not trained properly for the action they later find.
The other three are more professional, but misfits.
The characters are quite credible. There is more than what one sees on the surface. The leader, played by Richard Todd, seems calm and cool, but we learned he lost an earlier troop of three men who died under his command.
That's the real story, but it takes a few viewings to figure it out.
His second in command, played by Richard Harris, is a bully.
The third professional soldier, played by Ronald Frasier, is a Scotsman in an integrated group. It appears that all four of the countries are represented.
The main character is Bamforth, played by Laurence Harvey. He goes from antagonist to protagonist, and when these soldiers caputre a very meek and old Japanese soldier, Bamforth at first is ready to kill the prisoner, but later becomes the only one who speaks out to save the prisoner's life.
They are in close quarters, so for one soldier to shoot the prisoner is not an option, because more than likely, one of the other soldiers would get shot.
As the war drama progresses, we find that the Japanese have other soldiers close by, and we see how the leader lost his earlier patrol. He seems to be rational on the outside, but he makes decisions that can cost them all their lives.
At the end, an ironic fate awaits every soldier.