I think its the last one, but I'm not super sure. The extra play was kind of meant to give some commentary about the actual play.
Metaphor; its showing how that rack was moving alot-something like how a teeter totter would look had someone been playing on it. it was comparing the rack to a teeter totter
The answer is Nemo. Nemo was the one that got mad in that chapter, and the answer is verified.