how am I to know where you would stop escalating the violence you initiated?

With reason, logic, and evidence? Humans are emotional beings and they make emotional mistakes. If someone screws up and lets their negative emotions get the best of them, and you'd be willing to end their life because of it, that to me seems like a moral framework so rigid as to be worse than Statism's victimless crimes or some hyper-dogmatic, fundamentalist, violent worldview. Punishment based on harm done to the victim has to be rational. When it's not, we get the State or ISIS.