Then again, the officers that were injured during the storming of the capitol were also armed (though not with M4's), and still they were hurt. Sometimes a mob can get an advantage through shear numbers, and for obvious reasons the dudes with M4's may be slow/reticent to start firing automatic weapons into a crowd.

That's because it was merely a riot at that point. The scenario we're walking down is one wherein the #2 guy in the government is to be hunted down, captured and killed. That makes it deadly force scenario for Pence's protective detail and for any LEOs in the vicinity (who, in that scenario, are automatically deputized with the same Rules of Engagement that Pence's detail would have in a worst case scenario).

Not a bit, because although you say "the democrats," there were only a handful (sometimes only one) protest votes against certification. They never stormed and seized the U.S. Capitol. Nothing on this scale has ever happened with protesting a Presidential victory - either by the Congressbeings or by rioters.

Yeah. So? The 2020 inauguration was also beset by riots. Didn't slow anything down.
In our USA Up All Night B-movie scenario that we're outlining, even in the worst, worst case Biden's certification would have been slowed down by maybe all of...

...wait for it...

a couple of hours. Max.

But it is the ur-example of an insurrection, because the storming of the Bastille was a critical flashpoint in the revolution.

Okay. So were there mobs of Proud Boys ready to start erecting guillotines in and around Washington, D.C.?