As the elevator drops deep beneath Crucifix Bastion, Robert Langdon wrestles with claustrophobia and the uncertainty of what waits below, especially after realizing someone stole Brigita Gessner’s access card and even removed her thumb for biometrics. Katherine Solomon admits the descent feels unnervingly long, and Langdon notes his phone has fully died.

When the doors open, the space outside is pitch-black until overhead floodlights snap on, revealing a sleek, high-tech station that looks nothing like the ancient bastion above. The pair finds a minimalist maglev transport on a narrow-gauge track, with two wheelchairs strapped in the cargo area; they take the presence of the tram as a possible sign an intruder already came and left, but the automated system powering up also raises the fear that someone is monitoring them.

After chimes sound, the platform accelerates silently into a tight tunnel. Katherine and Langdon panic when a headlight appears dead ahead on the same track, but both vehicles shift into a widened passing loop, narrowly avoiding collision, then return to a single lane. The near-miss convinces Langdon the system is computer-timed, yet it also proves the tram network is active and not under their control.

The tram stops at a second, identical station where they pass an unmanned security checkpoint with scanners and desks. Through glass doors labeled Confirmation, motion-triggered lighting guides them into a pristine corridor. They ignore a dark side hall marked Support and follow the route toward Operations, seeking the facility’s core and hard proof of what Threshold is doing.

In an alcove, they enter through a door marked with a caduceus into what appears to be a secret hospital suite, including advanced imaging equipment, stocked medical supplies, and a room labeled Recovery with two beds. A crate on a forklift labeled “NIRS” alarms Katherine, who recognizes it as near-infrared spectroscopy used to monitor brain activity. Moving deeper, they reach a scrub room looking into a gleaming operating theater where an ominous, unfamiliar machine hangs over a surgical table, leaving Langdon convinced they have found something dangerous.