So I know this happens, because I've seen it happen before. But I don't know what to call it. You've been badly injured. You can tell that your someone's limb is mangled and bleeding. But you think the wounded body part belongs to someone else, and you're convinced that you're just fine, or at least not in as bad of a shape as that other guy. Obviously, severe trauma does a lot of weird things to a human mind, especially if it also comes with a head injury. But what do you call this particular phenomenon? "Depersonalization" is one term I've heard, but I think that might actually denote a deeper form of psychological distress.
Well, yes. Someone who suffers from what I'm describing is almost certainly in or about to be in shock. But that's a bit broad, methinks. It seems to cover a lot of what happens in the aftermath of a serious injury.
Although... that does remind me of something I saw in an otherwise forgettable action move. Bad guy gets his arm cut off by the hero, yells out to his minions. "KISS HIM!!!" "Uh, what?" "He's in shock. I think he means 'kill him.'"
I don't think this is quite what you're looking for, but it's closely related to a phantom limb, where the limb is missing but the person still believes it's there and seems to feel (phantom) pain in it.
That's almost the opposite of, and probably connected to, the absolutely terrifying condition where your body thinks that a healthy limb doesn't belong to you. https://en.wikipedia.org/wiki/Fraxinus_pennsylvanica EDIT: (speaking of derping) https://en.wikipedia.org/wiki/Somatoparaphrenia In both cases, whatever part of the brain is herping and derping to make it happen, I wouldn't be surprised if it relates to this.
It might be something like Dissociation. I think it happens to people for instance while being raped or physically or emotionally traumatized in ways they aren't able to accept, so they in a sense go outside of their body. Something similar (if not the same thing) happens with PTSD—a triggering experience can pull you 'out of your body' or make you feel like the things happening aren't real or are happening to somebody else. It sounds like you're looking for something more specific though, and I have no idea what that would be called.
Yup, the word I'm looking for is dissociation. Depersonalization (loss of sense of self) could be used to refer to a more specific form of the dissociation. That often happens in conjunction with derealization (loss of sense of reality), a separate but closely-related symptom. When one or both become chronic then it's known as depersonalization/derealization disorder. If the condition is more complex and PTSD-like, then it's Acute Stress Disorder (aka psychological shock).
