User blog comment:Miskos3/Fairy Tail Episode 259: Tartaros arc: 00:00, Review/@comment-25111584-20151114080356/@comment-7418318-20151114093522

Well... they are fighting in an area that's surrounded by relatively intact walls and did have to walk quite a ways to reach the control room, so maybe that's the reason.

Or maybe there are still some protective barriers in place. It was the nerve center of their operations after all, so having it protected would make sense.