Anonopine-

So, after the building was cleared of protesters you have a big crime scene. Both house & senate floors, the house chambers, and who knows what else.

Crime scenes have to be preserved.

You also have the possibility that someone left a bomb or bio agent, many had backpacks on.

How did they investigate and document everything and then do a security sweep and get them all back on the floor in such a short period of time?

I conclude they did not do either. And it shows that subconsciously, they are not concerned at all that Trump supporters might do something nefarious. Nor are they interested in fact finding regarding the crimes committed.