Kim tells me she has to sack something like 14 mice at work. The correct spelling is probably "sac," but this becomes problematic when I make it past tense, so I'm going with "sack." I assume the correct spelling is "sac" because she tells me it's short for "sacrifice."
Apparently, saying they have to inject the rodents with something that will kill them sounds harsher than it actually is. (In fact, it's quite descriptive of what it actually is) Therefore, "killed" has been nixed in favor of "sacrificed," shortened to "sac." This way, the creatures aren't being killed, but rather giving themselves for the good of mankind!
Fantastic! How noble of them!!!