She was climbing through a smashed and barricaded window into the final secured perimeter. There's another angle more from behind that shows she's was stepping through.
Not directly related, but it was absurd to see people defending the DC police in this thread. A complete and total failure at their mission and an easy and disturbing contrast to how they and many other police forces across the country handled police-brutality protesters throughout the summer.
Maybe they should have stopped these people? DC police have a half a fucking billion dollar budget. Law enforcement across the country have "intelligence fusion centers." This was all planned and discussed out in the open, and they were completely unprepared for it. Why? You don't even have to go down the rabbit hole of coordination or anything; they showed that at best they are deeply incompetent and incapable of carrying out their most basic functions. Tear it down and start over.