Brother your not the only one I nearly lost myself to Khorne the first time i watched that. Had to take a break from the game and play Warhammer 3 as the Ogres or I would have fallen to Khorne.Not sure if that is the plan if that is the plan does not change that the slaver's meat must be offered to the Great Maw and the Firemouth he is not worth eating.
Considering the faction i mentioned the level of insult it is for an Ogre to refuse to eat something after killing it is pretty high more so if the meat happens to be another Ogre. In fact this slaver barely is deserving of being sacrificed to the Great Maw and the Firemouth. Sadly the alternative leads to Khorne and I simply refuse to fall to a Chaos god for meat that isn't worth it.Though your alternative isn't so bad still feels far to much like mercy a death like that would be far quick. Butcher bring the pot to boil not for stew this one goes to the Maw