The Key
"He had the life expectancy of a match."
In wartime England, circa 1941, poorly-armed tugs are sent into "U-Boat Alley" to rescue damaged Allied ships. An American named David Ross arrives to captain one of these tugs. He's given a key by a fellow tugboat-man -- a key to an apartment and its pretty female resident. Should something happen to the friend, Ross can use the key.
Directors: Carol Reed
Writers: Carl Foreman, Jan de Hartog
Cast
IMDB: tt0051816