78RPMLife says:
He nods his head forward.
"Let's go," he says, and leads the way.
At the end of the first corridor, Erannik waves everyone by and then stops to fiddle with a small crank set into the wall at about knee level for an average-sized human. He cranks it several turns counterclockwise, and you can hear faint mechanical clanking sounds from farther down the corridor.
"Just a little surprise for anyone that might decide to follow. Anyone who doesn't know their way around, anyway," he says with a smirk and a twinkle to his eyes.
A short distance farther into the tunnels is enough to understand why Erannik was so concerned about people staying together. There are enough twists and turns and ups and downs that without a good map (written or mental), it would be easy to get lost.
It is at this point that the whitestone disk you carry begins to gently vibrate.