So it seems obvious that Stone is left behind while the Robotniks go to space. The scene where Stone goes “you kidding?” is probably Gerald saying he shouldn’t go, that it’s a “Robotnik” thing.
We know that Eggman wants to rule humanity, not destroy it. Not that he values it that much, but still. I think Gerald is on board with Shadow, that he wants to destroy the world, so it’s obvious that there will be a betrayal.
Gerald may try to convince Eggman otherwise, and he may get close, but I think that’s the purpose of having Stone on earth. So Eggman can remember that Stone is on earth, and he refuses to destroy him. I think *that* is what will make him change his mind 🥚🪨❤️