But council members do kill each other, especially when they're divided.

And the Lord Protector seems to have been offing more of them himself ever since they've been jousting around.

I live with and call your Death Eaters family. Harry has to call the Lord Protector Father, and bears the weight of responsibility if Daddy isn't pleased with him. Hydra - well, do I even need to say it? And Hermione sleeps in Buckingham Palace. Apologies if I sound unsympathetic to those of you who have to work with them, but I don't see the point in trying to predict what they'll do next because in the end, you can't. And if your prediction is right - well, good. Then you can prepare yourself for the fallout.