Meaning:
Lit. “his film reel snapped” which means the person referenced cannot recall her/his actions after having consumed a large amounts of alcohol and/or other drugs. It is quite often used by ethanol victims on the next day when asked what happened, where have you been or “do you remember what have you done”, which already suggests that something really embarrassing happened. In turn, they need to show their penance by saying: “nie wiem, zerwał mi się film” and await a sentence; being mocked by “pić trzeba umieć” (better) or hear some unbelievable details and then decide if they are just a joke or facts to face (worse).
The expression is an obvious reference to a defect of the old-fashioned movie equipment preventing from recording.