[Hey Commander, we have the trenching machine adjusted for mining. Who has the final blueprints for the bunkers?] Captain Tarsus asked the next morning, as the officers tried to get the chaos back under control.
The extra units were supposed to be staying a while, so senior staff had decided to burn off some of the pilfered fuel they had obtained to dig an underground complex below the village to hide their numbers.
Buildings and collapsed parking garages weren't going to cut it anymore, though they would make a great entry and exit point for the underground complex.
A bunker more than 30 meters below the surface, or 10 meters down and reinforced with Rock Crete could survive a low-yield orbital strike and would fully mask their Mecha's signature from orbital scans.