Self Defense or ?

It's 3AM in the morning in Dearborn Heights. A bloody faced African American young woman, intoxicated almost 3 times the legal limit, bangs incessantly on your front door. Not your neighbor's, but your front door. What to do? Is she armed? A threat? She refuses to leave, no doubt acting like the drunk crazy woman that she was, disorientated, who has been wandering your neighborhood for 2-1/2 hours. Again, what would you do? She is on your porch, in your face. Do you fear for your life? Detroit is just a few blocks away. Is this an act, a set up for a robbery? Do you ask her to wait a few minutes and be quiet while you find your cell phone and call 911? She won't wait. The shotgun is right there by the door. Not the phone. My take is that he threatened her off with the shotgun. We know the shotgun discharged by accident, that is an automatic 2 yrs jail time sentence right there, all gun owners must control their firearms, or face the consequences. But murder?