When somebody kicks in your front door that’s all the legal justification one needs to take the intruder down permanently. There’s no need to close and lock the doors to the rooms you retreat to.
Locking your bedroom door and leaving the woman with the intruder seems to be the actions of a coward, not a protector.
The fact the intruder went after the man indicates to me that he wasn’t a protector but her sex toy and the husband knew it too.
Not knowing the persons involved, that may be.
Could be to buy him time to load the pistol, too. Either way, the guy who was beating the woman is dead. As far as things between the two of them (if there was anything), well, that's between them. It sounds like a mess to me no matter how you look at it. It could be
A cheating woman/righteous but enraged husband shot by philandering feller
Victimized woman/rotten bastard shot by guy friend (no benefits).
...or anything in between.
There are plenty of possibilities, and I don't know any of them well enough to say.
Coward or tactical genius, one is alive and one isn't.
With what? His TV remote? His gun was upstairs, where he went to retrieve it.
There’s no need to close and lock the doors to the rooms you retreat to.
Unless you want to be able to get your gun from its storage place (and perhaps load it) without the intruder jumping you and possibly taking it from you.