The calls Loren frequently get from Monica, culminating in her ghost appearing to her.
Just every scene with Paymon himself. Especially the scene where he and two girls appear on a screen with the bags covering their face, with Paymon taking off his to reveal a satanic pentagram deeply cut on his face.
Holy god, the ending. After having spent all night seeing horror upon horror, Jessica is confronted by 3 more members of the Paymon cult. She's able to take them down with relative ease as they graduated from the Imperial Stormtrooper Marksmanship Academy. As she's holding the last one at gun-point, he decides to go for his gun, causing her to put a round in his head... only to be shot by Sgt. Cohen. While the viewer thinks he was in on it, Jessica finally sees the truth - those three men were actually the Hazmat crew coming in at 4 AM, and Cohen had shot her because she was gunning down innocent men.
