I think the main reason Franklin went back was so he could have the "you're doing WHAT with the telepaths?" scene on B5 and not on Mars. Which I can sort of see the necessity for; since this is the super secret plan, Sheridan wouldn't risk broadcasting it to Mars from B5, and Franklin did need to be told (and have time to be shocked) before the plan was actually set in motion, otherwise his going along with it without protest would have felt severely ooc.

Or vice versa?