From the hold of a civilian lifter
The skulls flew through the building. Mapping the area and assessing ingress and egress with efficiency sending the data to their controller. Should it be necessary to assist it would not be acceptable to be delayed by lack of knowledge regarding the layout of the building. Whilst waiting the controller also sent a request to the authorities for a floor plan and building schematic.
The controller sat motionless in the dark, his companion most likely getting more and more frustrated by the lack of action or even response. Though he would not admit it, this amused him somewhat.
A single skull hovered near the group entering the hall. It bore the cognomen, an image of a man with half the head replaced with a cog and a bionic arm. It broadcast standard vox codes for reinforcements and flew above the group, observing. Servants of the Imperium are never alone for though the enemies of man are legion the hands of the Emperor and the Omnissiah's guide. Vigilance is the Omnissiah's blessing and preservation is his will.