Amy showing off the more positive qualities of her angry and assertive personality. After being chased by Storm out of Meteor Tech and mastering her Arc Of The Cosmos, she finally confronts him by tossing her Arc Of The Cosmos at Storm, hitting him square in the beak. She then proceeds to completely dominate him and force him to find the way back for both of them.
Metal Sonic shows signs that he retained his backstabbing nature by simultaneously foiling Eggman's tournament gambit and gaining the racing data of the participants. After having the events of Heroes seemingly deleted from his memory.
It sorta plays into the rematch Sonic offered at the end of Heroes.
While it was mainly via cheating, you have to credit Jet for not only outdoing Sonic in the first tournament, but actually being one of very few foes to leave the usually mellow hedgehog brimming with rage.
Well according to the cutscene before metal city, the tournament was "No Holds Barred". Blowing up Sonic's board was totally allowed within that context. Sonic and co. were just too nice to employ those tactics for themselves.