If someone killed someone you loved, would you like to be able to choose whether you or your government puts them to death? If yes... how far would you like to be able to go? Would you want to pull the switch, shoot them in the head, beat them with a crowbar, or kill them with your bare hands like that guy did in 28 days later (the coolest thing i've ever seen in a movie)? If the killer was someone like Mike Tyson, then you might want the gun. Although, maybe you could have him tied down for a couple months so his muscles go away. Or maybe you could have it out with him in some isolated location where you can make crude weapons out of thing that you find in your environment.