Vibrating Sheet

The descent brought me back to the lower perimeter. In the dim mail alcove near the exit, a metal slot sat loosely open, shuddering with every passing draught from the street. It clattered in erratic pulses. I approached without haste. Grounding my stance against the tiled skirting, I pressed both clawed hands against the hinged brass plate. Heavy resistance met my force. I drove the metal flap inward until it locked into the magnetic catch with a firm, solid thud. The erratic clatter vanished. Only the low hum of street traffic resonates through the entry now.