OK the latest commercial from the artist formerly known as brinks.
Most of the commercials have an anonymous attacker, rape murder pillage leave (these may be able to be scared off). This is sooooo different; you have an enraged attacker kicking down the door to do bodily harm. He will be immediately identified by the victim, he knows it, and he does not care... If she does not survive he knows he will be tops on the suspect list. Even if a cop was standing there it might not change his course of action until he is shot. Once she sees him he has no reason to stop even if he had a conscious. SHE is the object of his anger and if he is still lucid enough to notice the loud noise it will probably just add to his anger if anything. (Still no reason not to have the alarm it does have its place. Just not as the last line of defense) this is where a restraining order can help her after she shoots his (censored) off and the DA gets involved.
When the EX kicks the door down she had better have a weapon available, not an expensive noisemaker, not a piece of paper to throw in his face. He is attacking on a visceral level, more akin to a wild animal than a self aware being. All of the other stuff is good before and after but at the Do or Die moment there is no more flight available, she has 2 choices Fight Back or DIE.
Sorry if this sounds more like a personal rant than a tactical discussion but this is an angry subject.