A few posts up, i posted the replay. if one has played bball, you would know when the ball goes up you start to put your butt into whomever is close/you’re guarding to establishes position. In this case Lance does that, but as Guerrier makes contact with Lance, I assume Lance understands Guerrier is a larger player, Lance puts more force into the box out to try to gain an advantage. However, Guerrier then rises up and thus “pulls the chair” from Lance and lances momentum/gravity makes lances body go backward and “undercuts (not on purpose)” Guerrier. No foul called on the floor, so from a few posts up, it seems all they could call was a flagrant…which at that point, is a huge momentum changer.