Capital Police opened the security line, encouraged the "protesters" inside, and were even shown having selfies taken with them. What other conclusion can you reach than that this was supported if not organized by someone with authority over the security forces sworn to protect the Capital? If true, this is Sedition.
At what time point in the video do you see the protesters break through the police line? I scanned through the 1.5 hour video and didn't find it. It seems like the whole video was filmed from the same location.
It's hard to tell but it looks like a door was either breached or opened to the far left. There is a loud thud happening at the same time but it's hard to tell if that's what caused it.
It's seems to be off the side of the barricades so it doesn't appear anyone was "let in".
I can confirm this, I saw a video on twitter showing the guards opening up the barricades and letting people get in. But they most likely were acting on an order to do so.