How 'bout we just have other death-row inmates do all the dirty work.
Number 2 kills Number 1; Number 3 kils Number 2; Number 4 kils Number 3; etc...
This way, if they
do end up feeling guilty about killing someone, (a.) it's probably not the first time, and (b.) they won't be feeling guilty about it much longer. (Even though it would be for the rest of their lives
)
Randy