Regarding today's discussion of "which Evil Overlord List entry is Krennic breaking at the moment" - this one seems like the most "on point"
http://tvtropes.org/pmwiki/pmwiki.ph...VowsCellblockB
194: If I offer to pay someone, I will keep the vow, and I won't kill them once they are no longer useful.
Although some others may apply as well - for example:
185: I will make all my minions pass psych eval and IQ tests. Idiot minions generally forget orders, and respond to such orders as "Kill her" or "Strap him down" with "But datz mean, boss!".
(meaning - don't employ minions that still have consciences).