Constantly rotating starship-style corridors inside the Reaver castle that only obey properly credentialed Reavers.
The interior of The Reaver Castle is a wall of honeycomb openings whose halls shift and rotate continuously. Tipid recognized the design from starships: with the right credentials the halls move you to your destination instantly, each room can seal into an escape pod during a hull breach, and it allows rapid response to damage, but with the system offline it is an unholy nightmare. Down here, he judged, it functions purely as a security feature, and he flatly said he would not want to go in there.
Katia worked out that the shifting follows a circling pattern and would only react if a Reaver entered, mapping it with Bautista tossing stuffed animals in and tracking how far they traveled. The honeycombs along the edges did not shift, and the top center opening was the passage to the Throne Room. Damage from the bombardment left the mechanism jerking and screeching metal on metal. Jamal climbed the wall like a spider and flamed opening after opening as Robot Doggies poured out.
A towering wall of hexagonal openings that jerk and rotate with a screeching metal-on-metal grind, edge cells static, deep interiors dark.
The castle's security maze, which deters the crawlers from taking the throne room and channels the sentry dog assault.