Casey didn't yell. Not like Titan had the first time Roark showed him the tunnels.
They weren't common knowledge because there was concern they'd be used to launch a sneak attack. He thanked every bone in his body that Theona had never learned of them. Although, even if she had, he'd left pitfalls in place purposely to thwart anyone who tried to navigate the passages.
The door at the bottom of the ladder had a keypad system. Not electric, those could run out of juice or get zapped by the volatile atmosphere. Instead he relied on a puzzle that didn't allow for errors and needed a little shove of magic to complete.