If someone starts beating on my door in the middle of the night, screaming about blood, injuries, and stabbing, I'm going to go into code red immediately. And I hate to say it, but criminals say things like "my friend is hurt, open the door so I can call 911" to get good people to unlock their doors, just like they wear shirts which say "POLICE" and say they have guns and warrants and you "need to open the door". If someone demands that I open the door to help, I refuse, and he keeps beating on the door trying to get in, I wouldn't hesitate for a moment to point a gun at him to make him stop.Sec. 9.32. DEADLY FORCE IN DEFENSE OF PERSON. (a) A person is justified in using deadly force against another:
(1) if the actor would be justified in using force against the other under Section 9.31; and
(2) when and to the degree the actor reasonably believes the deadly force is immediately necessary:
(A) to protect the actor against the other's use or attempted use of unlawful deadly force; or
(B) to prevent the other's imminent commission of aggravated kidnapping, murder, sexual assault, aggravated sexual assault, robbery, or aggravated robbery.
(b) The actor's belief under Subsection (a)(2) that the deadly force was immediately necessary as described by that subdivision is presumed to be reasonable if the actor:
(1) knew or had reason to believe that the person against whom the deadly force was used:
(A) unlawfully and with force entered, or was attempting to enter unlawfully and with force, the actor's occupied habitation, vehicle, or place of business or employment;
Now, we don't know the whole story, and presumptions can be rebutted in court. If there were a negligence clause in the law, this shooter would be a deep poop with the grand jury over him shooting through the door first and asking questions later... but negligence and recklessness aren't part of the castle doctrine, so I doubt he'll be charged. He'll probably feel like crap for the rest of his life, though. That's its own punishment.