These puzzies complainin bout sufferin should be made to make a choice:

-1- Die the way you killed your victim, least as close as we can get to it; or

-2- The needle.

Alla them puzzies will pick the needle.

Course, the answer is:

Nitrogen asphyxiation.

Sealed room w/windows.

Any guard can give em the pills to knock em out, then turn on the nitrogen and walk away.

Killers never know what hit em.