Given that it was time-lapse, she wasn't "slamming" the child on the floor -- in reality, she was gently lowering the child to the floor, raising the child, then gently lowering the child to the floor, over and over.
That's her story and she's sticking to it.
Ah! I gotcha--it was just a fun game she and the little tot were playing, and that dang nanny cam malfunctioned and made it look bad.
And when we saw the kid's neck whipping back and forth, in reality, the child was just performing several advanced yoga moves designed to over extend the neck. Gotcha!
Dang technology! ;-)