The drop box is just behind a large stamp machine, which was in use by a tall high-school kid, talking on his cell phone.
The bottom of the stamp machine had a sign. It read:
THE MACHINE GOES OFFLINE WHEN KICKED AND NEEDS TO BE REPAIRED
IF THIS CONTINUES, WE WILL REMOVE THE STAMP MACHINE
And the kid read the sign carefully, reared back, and gave the machine a swift kick.
The atrium was immediately filled with a siren-like wail as what was apparently a kicking alarm went off. And the kid smiled, continued with his cell conversation, and ambled into the main office to buy stamps.