You follow the same process as the previous visit, that is, ask for snus through the refrigerator, and at some point when you check at night she will appear.
In the first test, if the flask has little fluid, they are antis, and if it has a lot, then they are furries, although with Diane it's the opposite due to a visual bug
Nothing really happens, you just get a bad ending when there are only anti-furries and you kill Emi since she is apparently immortal against the anti-furries