the drift into the tunnels, hidden in plain sight
On most of the nontravel days that he doesn’t Big Buddy with his charges, Hal will wait till most everybody’s busy in the sauna and shower and stow his sticks in his locker and stroll casually down the cement steps into E.T.A.’s system of tunnels and chambers.
Context
The whole using-routine narrated as ordinary campus logistics: the wait for cover, the casual stow, the casual stroll into the tunnels, the drift back "substantially altered in mood" just as the fatigue-talk resumes. It reads as nothing because it is designed to read as nothing — the concealment is so practiced it disappears into the sentence's own flat itinerary, the same way it disappears into the day.