>>4768127This, you can see Cassidy jump up really high.
All Keith did was give him a little push, and Cassidy already had forward momentum from his own jump.
The nerds didn't anticipate this, stood still, and lacked momentum to adapt, thus Cassidy speared the concrete, which wouldn't have happened if either he wasn't so eager to jump or the nerds adapted.
Keith gave him an overhand push which is a difficult angle to push from.