They failed in two ways:
They were profoundly unprepared for a riot. They should have been able to block the rioters at the doors with no blood shed.
Then they let the rioters get in the building and endangered the members of Congress. They should have prevented the entrance. Probably warning shots would have done it. If not, then they needed to shoot some rioters.
There will be a major investigation. So your post is stupid.