You pour it down the sink and the three of you sit on the floor and drink the cheap stuff instead.
MalfoidBoring. Correct, but boring.
Nothing happens. That is the ending: a term that stops.
In the morning Mione is a prefect and Malfoid is a captain and Corvina is a teacher, and you go home on the slow train.
It is the only version where everybody is still in the same room a year later.