This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Jurassic Park: Trespasser
In one office in the lab level, there are 83 tally marks and the phrase "2 months" on a whiteboard. One of the hunters must have survived and been holed up in that building after being left behind. There are no bodies nearby, and neither voice-over makes a comment. The thought of being left alone of an island filled with hungry dinosaurs is scary enough, but the tally marks appear to be written in blood!
The diner in level 4, The Town. To elaborate. When you enter the diner, a raptor is spawned in the back, and the door is standing but off of its hinges. The raptor will often come in by knocking down the door and scaring the hell out of you.
Somewhat lessened when you find out Raptors can't go inside buildings without the ATX2 mod.