Let's imagine that you have created an AI that is capable of making realistic human behavior but doing so inevitably leads to full consciousness. So there is no way to have it seem human without being fully conscious.

In that case, you wouldn't have the individual NPCs reach have their own AI. Rather, you would have a single GM AI that controls all the characters. It wouldn't feel poison anymore then I feel pain when I write a story with realistic characters.

There is no circumstance I'm which it would be whether desirable or moral to create sapient entities for the style purpose of murdering them.