I think there should be a toll on the main character. Perhaps he's initially sickened by the first few deaths, but then they start wearing him down and he retreats into himself. That might be the whole point of all of the deaths. He's reacting by retreating and eventually it's going to blow. As long as there is some type of reaction from the main characters I think you're fine. It's when they hack through twenty of them without thought, move on to the next, hack through them, etc, and there's never any thought to what they're doing or how it might affect them that books go wrong.