With what limited information we have, its definitely a bad shoot. However, we do not have all the information, and probably never will.
I feel terribly for the victim, and utter disgust towards the shooter. If I were a juror, the only justification I'd accept for shooting through that door would be someone else shooting through on the other side at you. I dont care if they had a meat cleaver and were slashing it on the door and making holes in it. Shoot the guy when he breaks the door down and gets inside (you have a gun and the advantage of surprise at that point, right?). Even if your family is inside and you feel threatened, you arent threatened until the guy is actually inside regardless of your "feels". I'd be very interested to know if/when the shooter called 911.
Getting a conviction is a whole different story regardless of who is right or wrong.