Second defender, Taylor, slid off the ball and did not have the ball but rather had KML's left wrist on the side away from the main view.
All reports I have seen of the play have described it as a clean block, which may or may not be, but Slaughter in back has and extreme downward motion with her right arm, though it is hard to tell how much of KLM she got from any angle I saw.
Point is, these are very dangerous plays when one player, usually the shooter, is bent backwards from the peak. Whether they really are completely "clean" or not, and they rarely are, with that type of momentum between two players, bad things can happen.