The victim left cover. I would remain behind cover in my BR, unless their are innocent third parties in the house. No mention of children, if I recall. If he enters through the doorway -- the kill zone -- he will be shot again.
I suspect he has had enough of the gunfight. The intended victim turned about to me armed. The attacker thought he could have his way without push back. The attacker now has a new "perspective".
The victim took an unnecessary risk.
I'm retired LE and retired military, including six years in the Marine Corps. Cowering while there is a threat in my home is not an option. I will always advance so that I am in a position to neutralize any threat inside my home.