In the event of a massive attack from the Bretonia armed forces ( including battleships ), the Molly would rather evacuate the place ( a place they cannot help in that very case, as the infocard are saying ), than waste lifes; and simply autodestruct the station in their flight, not leave any valuable assets behind them.
On the other hand, i wonder if freeing a whole fleet to attack Belfast, wouldn't be uncovering Newcastle flanc from an attack othe gallic forces in the North of the system.
But it might be a gambit that the armed force would willing to play, considering it might worth the price.
NB1 : also, i don't think Mollys would rely on GRN in Newcastle, they're not allies, remember.
NB2 : Londonderry has been degyarded, and added to the mod lore.