You bring up a great point, H&H.
Most everything I've ever read (being an uninitiate of the "shoot an attcking bear" club) is that a (daylight) bear can run at 35 MPH & will do so at 10 yards, or so (do the math), from "under cover," as you have surprised 'im.
Many time one won't even have the chance to point a firearm (holstered handguns seem less likely to be an advantage here) in the thick(er) brush where one may have an encounter (AK-stuff especially).
Many other areas of encounter as I've heard which may present a different scenario of firearm employment, but if wondering about how to stop a charging bear, I'd want to have a big-bore handy, at post arms (at the least) & be ready for a one-shot break-it-down now! (& hopefully) stop - kill it later, but stop it now = break it!
As with hunting the bigger pigs in tight quarters, I don't care if I kill it ever, I only want to break it enough so it can't get at me.
Killin's for later .....
(call me a wimp ... )