Countdown to Extinction

Hagan left his laboratory on the thirty-sixth floor and began the slow descent to the Abyss. The creatures would be huddled together in the canteen now, grabbing at their food and stuffing it into their mouths. Would he have enough time? He had heard rumours of people who had descended and never returned.
Reaching the twentieth floor and the end of the floating staircase, he went through the hidden door into a small, cramped lobby. From here, two hundred steps spiralled downwards into the void below. He stepped onto the first stair and listened. The creatures were cunning. They could be waiting in the shadows for him, just around the corner.
He continued the spiral downwards, keeping his ears strained for the faintest whisper. Reaching the bottom, he opened the door in front of him a crack, ready to put all his weight behind it if the creatures were waiting.
He reeled back as the stench reached his nostrils. He could barely breathe.
The corridor beyond appeared empty. To the left could be heard snuffling and slurping. He slipped into the corridor and headed for the safely of the Outside Stores.
The heavy door resisted his touch. Footsteps were coming along the corridor. He put his shoulder to the door, ignoring the pain and slowly, it began to open. As the creatures’ footsteps reverberated along the passageway, he slipped inside.
A blast of cold air came in through the filters and his breathing became easier. At first, he thought the walls were lined with emaciated bodies, hung up on the walls in a strange ritual, but it was only the old-fashioned thermal suits, thick lined boots, gloves and protective hoods.
He inspected the suits, discarding any that had small holes or tears. He would be killed within seconds of stepping outside from the cold, or suffer a slow, painful death from the many diseases which were rumoured to roam unhindered across the land.
Pulling on one of the suits, he fastened the hood beneath his chin and tried a few steps. The boots were heavy and weighed him down. At his approach, the doors to the outside creaked open, letting in a blast of cold air that nearly knocked him off his feet.
Moving forward in the unfamiliar padded boots, he braced himself against the biting wind. The doors closed behind him and he was alone in a foreign and dangerous land.
Beyond the pod lay a rich and fertile plain crossed by a man on horseback. In the distance, a few grey slabs of stone were silhouetted against the sky like monoliths to a primitive religion, all that remained above ground of the Greystone Clinic where hundreds of Primitives lay frozen, awaiting resurrection. he had seen this Mirage before, except for the slabs.
He crossed to the pod slowly, lifting each leg and placing it in front of him until he could haul himself into pod’s interior and sink into the heated seat. His destination was Greystone Clinic
A thousand years ago, starving workers had descended on the clinic, incensed that precious resources were being used on those who inhabited the vault, but it had been built to withstand war, plague, earthquake, fire and flood and could withstand the crowds too.
It took only minutes before sliding silently to a halt in the newly constructed underground transport bay to the old clinic.
Security measures had not been changed since they were first installed, to deter anyone trying to break in, although who would want to venture out here?
Far away, an ancient computer creaked into life, the building echoing to its clicks and whirrs as it slowly began its series of checks. When it had finished, the doors ahead of him opened, revealing a moving staircase that descended into the depths below. He misjudged the right moment to step on to it and stumbled, grabbing the hand rail in time to stop himself tumbling down to the bottom.