LeftHandofGod
The soldiers who breach in are met with devastating gun-fire, both from the now armed workers, with weapons of unparelled potency from ages unknown, and the automatic turret fire, in a burst of multiple formats of projectiles, ranging from kinetics, to plasma, EMP, lasers, acids, if they want to take this, it will be a reprisal of Stalingrad.
Meanwhile...
The whole megastructure flips itself sideways, its artificial gravity generators working to keep the inside environment stable, as it points its huge top exhaust port towards the navy that recently arrived, projecting the constant stream of blazing white light at them, as about a hundred small fighters leave the dock and go towards the fleet.
(I mean, it's a megastructure, if you land with hundreds of thousands you'll likely be outnumbered XD
But don't worry, they are taking ground due to the unexperience of the workers)