Chapter 41, what is the purpose of labels for people?

The labels marked the "status" of the prisoners.

Tally’s spine as she read the labels on the doors.
“Interrogation Room One. Interrogation Room Two. Isolation Room One,” she whispered, her flashlight flickering across the words like an anxious firefly. “Disorientation Room One. Oh, David, they must be down here somewhere.”

Farther down the hall, a label caught Tally’s eye. “Long-Term Detention,” she whispered.