I guess you missed the 2nd takedown, considerably harder than the first, while she was handcuffed. Or maybe you didn’t miss it at all and don’t care what cops to handcuffed women.
To me it appears that the video was edited. Before each of the throw-downs, you see the video jump - indicating a missing section.
So - we don't really know what (if anything, to be fair to the woman), precipitated the officers actions.
I'm reserving judgment until I know why (or if) the video was modified...