You're trapped in a situation where you need to tolerate your bully roommates as you can't leave the apartment for some reason.

One rainy night they decided to carry you to a secluded concrete and lock you up,flashing their middle fingers on you,leaving you trapped there.

When you manage to get out from there and go home,you shout in terror as you see your dead roommates bathing their own blood,and notice a bloody note on the wall

"I saw what they did, you're safe now. -secret admirer."