if/when (someone) falls asleep
잠들면 안돼!
Don't fall asleep!
— 담뽀뽀 (1985)
잠들면 안 돼
Don't fall asleep.
— 퍼니 게임 (1997)
잠들면 안 돼요
You mustn't fall asleep.
— 타오르는 여인의 초상 (2019)