If you make a perfect copy, the identity has branched. There are now two distinct entities (with continuity) that are starting to diverge, why would any of them accept to be shot?
What if one did this regularly? Would battle-hardened cloners become insensitive to "retirement" of their doppelgangers, or as the last survivor of the series of slayings would they start to feel hunted?
Really feels at least a few centuries too early to even gauge whether it is possible to substantially capture (let alone reproduce) the state of a brain. Sure would be disappointing if it turned out you could get 90% of the functionality with a ten-state DFA featuring frowning and pooping, but it would make cryonics a whole lot easier. "Just leave me enough brainstem to get home."
But I take it I am unusual in this.