if they were all wasted how did they get home? I read the guy was not drinking and was their ride, and the one girl got hungry at 3am or something and was lucid to order door dash.
but yes if they were alert likely they might be alive and had the other girl in her room by herself likely with the door locked, she woke up and heard something, saw something and as quite and he did not see her, she is alive.
two girls on the top floor apparently had their doors unlocked along with the guy, the girl got surprised when she got her food and she was defenseless.