What a night you had! I hope you were able to get at least a little rest. It sounds to me that you handled this perfectly, and good for you. Many ladies would have either been goodhearted and opened the door, or panicked. You did neither.
Now personally, I think the sound of a round being chambered in a shotgun a fabulous deterrent. No need to open the door, they'll hear it. My plan is to never have to actually fire the thing, 'cuz I'd be in pain for weeks if I did.