Oh, forgot to mention in my other post- I go over this exact sort of thing when my department does it’s bi-annual Active Shooter training.
Is there any reason you can think of why you wouldn’t be responsible if you shoot and kill a bystander by accident? That’s the very definition of “Manslaughter,” NDCC 12.1-06-02, or, if you get a particularly liberal prosecutor, “Negligent Homicide,” NDCC 12.1-06-03.
And one more time, just for the record- Dark. Tear gas. He has a gas mask and a rifle. You have a pistol. He’s looking to kill anything moving. You’re looking to kill him specifically. Good luck hitting him.