Texas law allows use of deadly force when defending a victim against sexual assault and kidnapping both of which applied in the Texas case. It was a simple decision for the Grand Jury:
Sec. 9.31. SELF-DEFENSE
a person is justified in using force against another when and to the degree the actor reasonably believes the force is immediately necessary to protect the actor against the other’s use or attempted use of unlawful force. The actor’s belief that the force was immediately necessary as described by this subsection is presumed to be reasonable if the actor:
(1) knew or had reason to believe that the person against whom the 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;
(B) unlawfully and with force removed, or was attempting to remove unlawfully and with force, the actor from the actor’s habitation, vehicle, or place of business or employment; or
(C) was committing or attempting to commit aggravated kidnapping, murder, sexual assault, aggravated sexual assault, robbery, or aggravated robbery;
whoops grabbed the Self Defense instead of
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.