Kill an enemy using a trapPOTENTIALLY MISSABLE
There are two types of traps in the game, the Armored Knights in the Hospital and the Spike Traps in the Bunker and to get this trophy, you will need to kill an enemy with one of these traps.
The first place you can do this (and potentially the easiest) is at the E-2F Dining Room Hallway, in this corridor there is a Wheelchair close to the Main Hall exit and a set of armored knights by the door that overlooks the Library. For the trophy, just lure the Wheelchair by walking slowly as you get close to the armored knights and when it gets close, run past the trap activating it along the way. If you got it right, the Wheelchair will pass through as soon as their lower their swords and will die in one hit.
If you prefer a visual guide, you can watch the following video: