> Aren’t a fire truck’s lights and siren on the entire route to the house? <
I’m guessing the firemen wouldn’t use their lights and sirens on a welfare check. Which this situation was.
And I’m guessing the police wouldn’t use their lights and sirens when responding to, say, reports of a prowler.
What I’m suggesting here is this: lights and sirens on the way (or not), use them the instant you break through a person’s front door.
IMO, that is way too late. General thumb I've heard is that at the point an intruder breaks in the door and starts to enter, they can be shot.