What incident takes place in science class?

Camelia and Ben work as lab partners in science. Ben continues ignoring Camelia's attempts to make small-talk. When she and Mr. Swenson tell Ben he should feel the tube of laxative solution they are mixing, Ben's fingers graze Camelia's, and he drops the tube. Swenson tells Ben to clean it up, but Camelia makes the move to do so. Ben seizes her wrist to stop her, and everyone begins talking. Swenson tells Ben to let go of her and to head to the office, which he does. Swenson then asks Camelia if she has been harmed, and Camelia says she is fine.