Scourge

Arrianna, Atomic Sprout, and Joe Mage are completely correct. We humans are flawed and there for will never be perfect so its very stupid to assume that by constantly "tweaking" the system that it will be perfect some day, but that fact is that day will NEVER come. Because people are imperfect creatures, we make mistakes, thus leaving the door open, even just for a short amount of time; some one will take advantage of that. The guards are only human and so will make mistakes, which the murdering type of convicts will take full advantage of and us it to kill some one.
Also on the note of Luminous statement of leaving them in prison with just four walls and a roof over their head with a two and a half inch metal door with nothing more then a little slit to drop food off, well guess what, we have those already, and oh guess what again, the people still manage to kill EVEN INSIDE THERE OWN CELL!! I have seen a lot of hand made weapons by prisoners and one of them was a sharpened stiraphome blade made out of a paper plate which was use to kill another in mate. So far the most remarkable weapon made was in fact a crossbow made out of news paper and other books, same as the arrow its self and uses the elastic waste band from his underwear to fire his arrow. The killer was able to kill a guard walking by, by shooting him in the neck from the little food slot.
Now you will say then why don’t they do a search for these things, well again, they do, but prisoners are very resourceful and will hide stuff in the damndest places. I will just let you think about that for a moment.
As said before, it is very hard to hit some one in a "safe spot" on the body with a gun. Not only do you risk of missing and hitting another person on accident, but if you do hit your attacker in the legs or arm you can still very well kill them as you also risk hitting an artery. Not that would matter much to me as I would defend my self with lethal force when necessary, but I would still much rather leave the shooting to the cops as they have better skill with a gun then I do.
I know a few hand to hand moves that will dislocate a persons arm and legs, and even break bone, but the fact is this, if I was taken by surprise which is most often the case in these murders then my fighting styles don’t mean anything. Especially if they have a gun.