Babbit is surrounded by anything BUT uniforms.
The shot had already occurred when young SWAT shows up, sort'a pulls up, and drops for a thumbs up
Sullivan has been reported as talking them away from the doors.
They are pretty much directly behind and a bit to one side of the doors and Ashley when she is shot and drops back into the crowd, away from the window in the door she was attempting to crawl through.
They were about 10 -15 feet from Ashly, as I recall, when she was shot.
There are multiple videos of the scene out there.
We may easily be looking at different videos.
It shows the swat team coming up the stair well.
It is not the video I saw, but it does show the Capitol Police with rifles just a few feet from Ashli when she was shot, but from a much different angle.
It isn't on of the officers from the door that raises the rifle, it is one of the tactical officers, and it is a few seconds after Ashli was shot, not immediate, and not minutes.
The obvious reason for giving the thumbs up, is he identified the shooter as a fellow officer, and not some freelancer he might need to engage.