How does Bruno's father's office compare with the rest of the house?

Bruno's father's office is a veritable hive of activity, with all kinds of important-looking people going in and out at all hours of the day. It's strictly out of bounds to the young boy and his sister, and it's made very clear to them that this is not a playroom. The children are perfectly free to play anywhere else in the large house, but not here. Their games stop outside the office door.
Bruno is suitably intrigued. After all, if you tell a child that a certain place is off-limits, they'll be all the more curious about it. But Bruno's too well-behaved, too naive, to defy his father's express orders. Nevertheless, he does get to see inside his father's inner sanctum on a few rare occasions. Even then, he's much too nervous to pay much attention at what's going on around him. The office just seems incredibly busy, with fast-typing secretaries and numerous men in uniform. A more different environment to a playroom would be harder to imagine.