There are many different flavors of mobs and the mob flavor will be a determinate. The Grab-N-Git bunch on the OP video should be given distance and little interference, which, in my view, is true of any mob; however, it’s the unavoidable or inescapable mob geared up for violence, aka the bunch at the state fair, that presents a problem. No easy answers come to mind, but having a concealed firearm would definitely be better than not.
While it is true that mobs have overcome someone with a weapon or gun, I would think there more instances that a crowd clears the area when the shooting starts.
The OP asks if you would try to help or defend in a mob situation. Your state law will play a part in the equation. Some states will “allow” intervention, some will not.
A lack of planning on your part does not necessarily constitute an emergency on my part.