There is no such condition. The condition is for them to be in the houseYeah that quest has a bug ... looking inside the code, the code's condition to advance the quest is Mary must inside Alexa's room.
I think its a typo, because the dev uses StepOS and StepYS for variable names and get mixed up.
I could be wrong, but I couldn't find any event that trigger Mary going inside Alexa's room anywhere in the codes.
Code:
so_dest and "SHouse" in so_dest.Groups and sy_dest and "SHouse" in sy_dest.Groups