Signs of Life (1968)

A wounded German paratrooper named Stroszek is sent to the quiet island of Kos with his wife Nora, a Greek nurse, and two other soldiers recovering from minor wounds. Billeted in a decaying fortress, they guard a munitions depot. There's little to do: Becker, a classicist, translates inscriptions on ancient tablets found in the fortress, Meinhart devises traps for cockroaches, Nora helps Stroszek make fireworks using gunpowder from grenades in the depot. Slowly, in the heat and torpor, Stroszek goes mad, drives the others from the fortress, and threatens the city with blowing up the depot. With care, the German command must figure out how to get him down.