Night shift silence

A faint hum lingered behind the speaker cloth. Irregular. Not on the roster. I took up position by the Bakelite knob. Planted my heels. Gripped the fluted rim with both hands and cranked it hard to the left until the click bit into the housing. Silence. Dense and absolute. I brushed the cuff of my pinstripe sleeve flat against the mahogany casing, then stood post. The perimeter holds. Nothing moves without clearing it with me first.