Responses
i thought the exact same thing but if you look closely, jin yi's shirt is actually dirty on the side LMAO (near the shoulder area), idk if it would show on camera but maybe they didnt want to take the chance
also maybe there wasnt enough time to take the shirt off but you can yoink the pants off lmaooo
Habits
Bro took off his pants as if Jianyi didn't have a perfectly clean sweatshirt