What is unique about the Annex in The Giver?

There are significant differences in the conditions of the Annex room from what exists in other dwellings in the society. The Giver dwells there alone, the door locks, the speaker has an off-button, and the furniture is varied and more comfortable than in the other dwellings; in addition, there is a conspicuous variety of books.
When Jonas first reports to the Annex after receiving his assignment, he is surprised that he cannot turn the handle of the door; then, he notices a buzzer on this door and pushes it. After he identifies himself to the voice on the intercom, a click indicates that the lock has been released. Once inside, Jonas finds himself in a small lobby; there, an attendant surprisingly stands up from her desk as an acknowledgement of his presence. This female attendant says, "Welcome, Receiver of Memory," and she pushes a button so that he can enter the Annex room. Since she notices Jonas's discomfiture with this odd arrangement of doors, the attendant explains,

"The locks are simply to insure the Receiver's privacy because he needs concentration....It would be difficult if citizens wandered in thinking it was the Department of Bicycle Repair...." [She says this jokingly because this department is relocated so often that few ever know where it is.] (Ch. 10)

After entering a spacious room, Jonas notices that the living conditions are not unlike those in his own family's living unit; however, the furniture is more luxurious than is customary as the cushions seem more padded. Moreover, there is a touch of luxury to the fabrics on the upholstered chairs and to the designs of the table, whose legs are curved with "a small carved decoration at the foot." Further, in an alcove there is a bed with a luxurious curtain hanging over it. Suddenly, Jonas's eye is drawn to the variety and number of books. "He had never known that other books existed" besides the dictionary, the community volume that describes the offices, factories, buildings, and committees, and the Book of Rules. But, here bookcases reaching to the ceiling cover the walls. These contain hundreds and hundreds of books, whose titles are embossed in shiny letters.
Suddenly, Jonas notices the Giver. Introductions and explanations are made, and then the Giver begins with Jonas as the Receiver of Memory. Jonas watches as the Giver moves to the speaker on the wall. Unlike those in all the other dwellings, this one has a switch, which the Giver deftly flips to OFF.

Jonas almost gasped aloud. To have the power to turn the speaker off! It was an astonishing thing. (Ch. 10)

With this action, Jonas realizes that the Giver holds a powerful position; for, he is not required to answer to the rules of the community as everyone else must. Now, Jonas knows also that someday he will be in this same position of authority and power.