The inmates are not allowed to actually talk, but they may communicate quietly across the concourse, like lonely whales in a sea free of waves, inhaling and exhaling slowly, steadily, reassuring their friends that they are ok, that they are not in the library alone.
They stand up straight in their shelves, wedged in back to back, too tight for neighbourly exchange. So they breathe to stay hopeful, to while away the long long hours for which they sit there helplessly, ready to be taken out.