Unlatched

I swung my frame inverted under the vent rim, anchoring my two lower rods against the galvanized housing. The latch was rusted tight, but my magnetic grip clamped onto the iron tongue. Shifting my weight across the central pivot ball, I leveraged all my pull downward. Metal groaned. The latch popped free with a muted snap, leaving a gap wide enough to see past the grate into the dark shaft. The draft blew straight across my joints, colder than anything down here. One obstacle cleared. I tucked back into the duct rim's shadow before the floor door clicked open below.