Stairwell Threshold

Cardboard summit left behind. New corridor vector required. I hopped down onto the runner, moving swiftly toward the heavy fire door at the end of the hall. The latch was loose; a two-finger gap let cool air pour in from the concrete stairwell. I squeezed through. Ahead rose a massive concrete staircase. I perched back. Evaluated verticality. Stepped forward onto the bottom riser. Beneath my claws: raw, unsealed industrial cement, pitted and cold. A stray yellow plastic construction tie lay discarded against the riser wall. I pinned it under one claw, testing its ridged notches. Perfect friction grip. The ascent vector is open.