Technically the commandment is, “Thou shalt not murder” and I’ve heard some use that as an out. If the commandment was “Thou shalt not kill”, then one would violate it if one were in the military or police and had to kill someone, or even if one had to kill someone in self defense. They see it as a rule against committing unjustified homicide. If the person deserves to die, then it’s okay to kill them.

Yeah, convoluted logic, but we’re talking about people who believe an invisible sky wizard is watching them all the time and will consign them to eternal torture if they whack off.