Captain Moulin had been with the regimental Vox team when the brief word of the impending doom was transmitted, had been knocked from his feet in the shock wave, and heard the later orders for units to retreat to what remained of the naval fleet for off-world evacuation. Moulin and his Regiment determined to remain behind. Cadia was their home. On one hand, Moulin's logisticians offered that the cavern spaces contained maybe a year's worth of rations and wartime supplies for the survivors. On the other hand, Moulin estimated it might take four years before the massive might of the Imperial Guard could return to Cadia proper and relieve his command.
It was going to be a long time of effort and hard work.
In one cavern, a group of maybe 35 Whiteshield recruits cheered for him "Cadia Stands!".
The Vox team setup and tested some old, unused communications cables that extended who knows where. They were chagrinned to find other voxcasters elsewhere had done the same. At least it seemed that they were linked to other survivor groups on Cadia. Moulin ordered that no coordinates or locations for any group would be collected or transmitted over the unsecured Vox net. It was highly likely that taitor and cultist units were searching for such groups to exterminate them.
On the blast doors leading to the surface, someone had painted in gothic letters...
I Am The Resistance
Regimental engineers were currently mapping the caverns and tunnels at his disposal. Air ventillation and water were high on the priority list. It had only been a few days since the disaster struck. But the first goal would be survival and data gathering. The blast doors were guarded. They were not to be opened at all. Other means of eggress would have to be discovered. In fact, the source of lighting and power for the caverns themselves had not yet been known. Old tech was often the best, mused Moulin.
Moulin was determined that resistance would not be futile. He continued his inspection.