I wonder why you folks are talking about long guns. If such a thing happens, chances are, what? 99%, that you will have only your daily carry piece.
The only recent time I know of where long guns came in handy was at the Texas Tower incident, where, apparently, some ordinary citizen(s?) went back to their truck(s) to recover rifle(s), which were instrumental in delivering suppressive fire.
Oh, and I guess, stretching it, the LA riots.
There may be others, but I don't remember them.
For myself, a handgun with laser sights will have to do. I mounted lasers on both my carry guns. And I suspect (tacticians can challenge me on this) that just painting the creep's general area with the laser dot will be pretty effective as a suppressant itself.
However like tracers, lasers probably work in both directions.
Yes, I've thought of that, too. Nevertheless, given an opportunity to do so with the safety of others in mind, that's my contingency plan.
I may get lucky, or I may get very unlucky, but as I said, I've made some surprisingly "lucky" shots in my day.
PS. I have become a strong believer in laser sights for personal defense arms, especially for those of us of advanced age. One attractive feature of them is that you can fire from hip or belly level in low lighting conditions without the muzzle flash blinding you momentarily. I found that out with my 2" J-frame with +P ammo, which resembles a Fourth of July Aerial Salute when it goes off in dim light.