Pretty rational, safe way to be in the midst of a zombie apocalypse, if you ask me.
CJ is business-like and clinical indeed. But I think that's a pretty normal reaction when so many around you have died horrifically. Some people go in for making human connections,
others go in for shutting down, and self-protection. And to be honest, its the latter type that would probably do better in the acute stages of a zombie-eat-person world.
I'm not saying that CJ has always made the right decisions, or is a great leader or anything. But I can totally understand her character traits that everyone else seems to so dislike.