Garry’s Mod isn’t happy when you trigger_remove entities that you are holding with the Physics Gun. Placing the NPC into a hole and pressing a button to remove it not only solidified what I was trying to accomplish, but stopped the crash.
I confirmed this by trying to do it with a prop_physics_multiplayer instead, and it was able to be deleted while holding the prop with the Physics Gun. Once I picked up a ragdoll, any ragdoll, with the Physics Gun and touched the remover, it crashed.
Solved and I hope this is useful for someone else!