Well, there's also the possibility that he'll be high on the food chain in prison - he's obviously one sick mofo, so he could do it, too. Many prisoners would be afraid of him.
Now, remember, life in prison may sound bad(and it is) but it's not as bad as you might think. Prisoners get a lot of luxuries that they shouldn't have, and they aren't worked like they should be. I'd consent to getting rid of the death penalty if we could actually make life imprisonment a punishment of the same degree.
I totally agree with you that prison ought to be a LOT worse than it currently is. I'd prefer that prison was seen as more of a deterrent to potential criminals than the death penalty.
Actually the story of the man who raped a girl and cut off her arms does not end where I left it. The felon served his time (15 years I think) and was released, despite objections from his victim. Within two years he struck again, this time by murdering a prostitute. So in this case the death penalty would not only have been a just punishment but it would also have prevented a murder.
I don't know how effective the death penalty is for deterring would-be murderers, but it most assuredly deters the person who gets it.
IMHO, the bastard should have been left to rot in jail. Obviously they couldn't have known he'd re-offend when they sentenced him for the first crime, but IMO the first crime alone would have been enough to warrant jail for the rest of his actual life. If it were up to me (steps up to soapbox), I'd make a LOT more crimes have actual life sentences with no chance of release. And I'd get rid of the death penalty. I can't think of one crime where the death penalty is a better solution thatn the ones I've already listed here.