You take the elevator up to the first floor at ground level.
The elevator ("3a") opens onto a reception area (marked as "1"). There is a reception, concierge counter--which has video monitors to monitor security around the facility. You are on the employee side. On the far side, you see the entry into the sanitorium, along with some couches and plants in a very relaxing atmosphere. There is a security camera to the northwest of the elevator that scans the room constantly. Monitors are on this side of the counter.
At the place marked with the star sits an armed commando staring at the security computer monitors. He slowly begins to turn in his seat as the elevator dings and the doors open, as if expecting to see someone else working at the facility--not armed strangers.