In all likely-hood, it will most likely make sense in the movie... we know that Cobra/Mars attacks the PIT, so maybe after the attack it converts into some kinda Mobile Command Center.

Thats my guess, and depending on how big it really is, I may or may not give Hasbro the $100.00. I already plan to fund Hasbro's payroll department with the new Resolute and RoC figures coming out, so getting the MCC/PIT isn't too far fetched.