Just talk to them? Ask Mobius about how to reason with them I guess. That might unlock additional lines.

It's probably one of those Dean Domino situations, dialog and actions you've done in previous may have affected the game to come to this conclusion.

Have you been exploring?

Been everywhere, guess I haven't said the right things to them previously.

You HAVE to help all the Think Tanks and not kill Mobius.

You had to have done each tank member's sidequest to get them on your side.

sixing up Dala, dealing with the dog for Borous, figuring out how to talk to 8, and talking to 0 about his name.

Alternatively, there's a dialog option where you claim that you're actually Mobius, which requires a high speech and/or science to pull off.

Damn, I did all that but the thing with Dr O, I don't have 65 Speech and don't want it either; guess I'll just bite the bullet.

You either can lie telling them you let him live, or say his brain is in your head.

Or you can bring muggy in, I always solve the problem the right way.

Not True, I killed mobius and was still able to reason with them.

I told Mobius I wanted my brain, convinced my brain to come with, then lied and said I implanted Mobius' brain inside my skull. Now the think tank works for me.
Checks for the lie are 100 Speech or 75 Science I beleive. Or vice-versa.