BBM:Respectfully and just imho:
Personally, if I was in a panic and fear of my life I probably wouldn't lock the door either. I'd get to my weapon to secure myself. It isn't a horror movie where one has no defense and locks the door to keep the bad guy out. The fact that he couldn't catch up to her, idk.
Looks like that went right over the prosecutor's head and the house layout for a possible closer exit which wouldn't have involved a firearm.
Something about AB's timeline after she started running to her room I find questionable.