못 들어가게

so that one can't enter

→ 못
phrase Rare #13,806
so that one can't enter 못 means “cannot” or “be unable to,” 들어가다 means “to enter,” and -게 makes the phrase describe the purpose or result of an action.
KO: 문을 잠가서 아무도 못 들어가게 했어요.
EN: I locked the door so that nobody could enter.

경찰이 보호하고 있는데 아무도 못 들어가게

The police are guarding it, so keep everyone out.

— 달콤한 인생 (1960)