Every individual has a right to protect his/her life and property. If someone breaks into a house the individual has a right and an obligation to repel the invader by deadly force if needed. If the invader is a plainclothes policeman intruding into the wrong house, the invader may be killed. And that would be justified.
In this situation the homeowner didn't have a chance to protect him/herself and you can see what happens. If the innocent homeowner moves in the "wrong" direction, he/she is shot.
And tyranny and terrorism by government marches forward.
Big advantage here is the homeowner got a good look at the fake undercover guys so he'll be able to obtain satisfaction someday if he wishes.