פירוש על עבודה זרה 120:8

According to the mishnah, if a non-Jew falls into a vat of wine, the wine may be sold (R. Shimon allows it to be drunk). R. Papa says this is true only if the non-Jew dies in the vat (ewww, not sure I’d want to drink it after that). If he comes out then the wine is strictly prohibited because we can assume that he libated some of it. Surviving the fall into the wine vat is cause for him to celebrate as he would on a festival.