They are overjoyed. Not at the odds, those are bad, but that Mike said "us." Aw—he'll be on their side.
Mike is chosen as chairman of the revolution, and the other three agree to never mention Mike's existence. Their little secret.
They begin planning the revolution and agree that Mannie and Prof should go about their normal routines. They'll contact each other through Mike, where it's safe and secure.
Next, they need to settle the basic problem of how they are going to defeat a giant like Terra.