Mara electrobinoculars

Vehicles with proper authorization were allowed inside without any fuss, but Mara could see as the gate closed that each was then stopped between the wall and the palace for a search. With her electrobinoculars' audio capabilities, she'd also eavesdropped on the guards' orders to the inside gatekeepers, and it was clear that a system of rolling passwords was in use.

Clearly, no one was getting in without a battalion of armored troops or invitation from someone already inside.