Chair three is in a room of its own at the back with a door that shuts, no window onto the corridor and nothing on the walls. It is the chair we put anybody who has written anxious in the notes.
The drill in that room is the same drill. What is different is that nobody walks past, you cannot hear reception, and the appointment is booked with ten minutes of slack after it so that nothing has to be rushed.
Ask for it on the booking form by picking chair three, or write it in the notes and reception will move you. There is no extra charge and there never will be.