They knew they would not be fired up on. They knew they had the numbers and just in case the police started shootingYou really need to seek mental health services. Considering they had no real armaments, they had no real body armor. No one with half a brain could even begin to think that they would have a chance against even a badly trained national guard unit little own the army.
But hey you do crazy all you want.
They had a cache of arms minutes away prepared for such an occasion. Why do you think trump offered Pelosi more troops ? No paper backup however. But he said he made the offer.