ainatan said:The amount of Hit Points lost determines the gravity/type/location of the wound, not the contrary.
Precisely. If the answer isn't "all of them" then you can't have suffered a lethal blow. Thus, if you want your system to treat a shotgun blast to the face as a lethal blow, you can only use that description after rolling damage and checking to see if you got "all of them". Otherwise, the wound is decidedly non-fatal.
This has nothing to do with healing surges at all. You can't use any HP system without this being fundamentally true.