SEGA said that this peculiar part of the “Fist Bump” soundtrack was going to appear at a very important part in the game. Everyone’s saying that it didn’t appear in the promised “important scene”, but it did in Null Space. Unfortunately, it wasn’t executed well.
I’m a sucker for symbolism and motifs, so here goes:
A big motif in the game is friendship and the strength that comes from it. Against all odds, what with Eggman owning nearly all the world and Infinite being virtually unstoppable, Sonic and co. managed to win and it’s mostly because they worked together.
In the scene where Eggman puts Sonic into Null Space, he wasn’t counting on the Avatar to get sucked in as well. He was intending to put Sonic in alone, giving him no chance of escape. However, because the Avatar showed up and, against Sonic’s words (“Buddy, no! You’ll get sucked in, too!”), the Avatar sacrifices his/her own safety for a rescue attempt. They both end up in Null Space together, and it’s only together that they can complete a Double Boost, allowing them to escape.
The scene and the relationship between Sonic and Avatar also acts as a foil to the character of Infinite, who seems to think very lowly of friendship and teamwork. Lo and behold, it is Infinite who creates the pocket of Null Space that was supposed to keep Sonic – who was supposed to be alone – trapped forever.
When Sonic and the Avatar escape Null Space, the rest of “Fist Bump” plays, which is a song that focuses entirely on teamwork.