Take a deep breath.
Background - many classes in structure takedown/hostage.
1. if you think that you are going to do it successfully without appropriate training, you will be dreaming. With training,you become cognizant of areas of fire, ballistics, penetration and gain confidence.
The guy who buys the Mossberg and blasts away may or may not have problems.
2. you need to drill your family about what to do in an emergency. I have a friend who trained his daughter what to do if she is in bed and there is a home fire. All you need is your people running around out of control, right?
I am not concerned about over penetration. You might. Do you think that you can consistently do head shots in low light in a hostage or potential hostage situation? No, you really can't. So you decide whether you use slugs or #8. #8 would not penetrate through a wall. COnversely, it might not put out someone's lights either. Your choice!
As for using an AR - I have built them from scratch, trained with them and all that jazz. Unless you use optics or a mounted flashlight or an eotech, they are exceptionally lousy for close in shooting in low light.The iron sights are way set off from the bore axis!
Some further comments.
I do some training. We have select slug drills. You act like you have the wrong ammo in the shotgun and go for a slug for between the eye shots in a hostage situation. Yeah, I agree, the drill is quite stupid. It is the end of a couple of long days. Ok, so I do the drill and take the bg out with a shot between the eyes. The instructor raves. I ask the instuctor why I have to use a slug when I had OO buck in the shotgun and I can shoot that well. His answer was that there was no guarantee that OO would take some one out across the room. Well, guys, if that is true, then what is the garbage about overpenetration - and you putting yourself at risk of death because you were forced to use no. 8 shot???
Why not train well enough that you can shoot a pistol, in low light, in strong side retention, with shots to the base of the throat? Same result, right? If your response is that you don't have the time or money to learn and practice perfectly, then why would you assume that you are going to spend the time and money to use a shotgun or rifle under the same conditions?