At the end of the game, after Metal Sonic is defeated, and Sonic delivers the "Because we're Sonic Heroes!" line, all of the other characters go about their business with each other and leave Metal Sonic lying on the ground alone...except for Omega, another robot himself, who stops to pick up Metal Sonic.
Shadow stands there with him and they exchange a glance. Seeing as these two were at each others' throats at the beginning of the game, this is a fairly sweet (and somewhat sad) moment.
When Sonic is about to take on Metal Sonic solo, what do Tails and Knuckles do? They step right in to help their teammate/friend with no hesitation.