Sam did not want to move. She feared that if she did, her head would crack wide open along all the parts that hurt, and her brain would spill out. But her throat squeezed and bile filled her mouth, and she had to roll over or choke on it. Light felt like a magnesium flare in her eyes, and she just managed to brace her torso, before her stomach ejected the remains of her last meal. It splattered her hands, and she croaked, “Oh,” and coughed, “bollocks.”
She levered herself with deliberate care onto her knees, and settled there to look around. Her eyes did not want to focus, though she confirmed with a finger that she still wore her glasses. “All right,” she complained, as she raised one hand to investigate the center of her head's agony, but stopped as she felt the vomit drip from her fingers and so set it down again, “What in hell happened just now?”
“Earthquake,” Ralph's voice came from one side, recognizable though thick with pain. Sam squinted in that direction, and made out a blurred outline that fit his proportions. He cried out as he sat up, like her content to fold his legs under him. “You ok?”
Sam laughed, the sound bitter as the taste in her mouth. “I think I have a concussion,” she told him, and the admission started the room revolving in languid, lopsided circles around her.  She leaned forward to brace herself on her hands again, and wished for some water to wash them and her mouth. “I can hear it in your voice, too,” she told him. “Where are you hurt?”
“Shoulder,” Ralph groaned, and Sam thought she saw him reach across with his other arm to probe the joint. “Out of socket.”
“I'll help you put it back in,” she offered, “as soon as the room stops spinning.”
“I've had your bedside manner,” Ralph retorted with a caustic laugh. “Think I'll take my chances on my own.” His head turned, and Sam heard him gasp.
“Sod off,” she advised, head down. “And it couldn't have been an earthquake.  We're a thousand klicks from the nearest active fault. That's why they located the project here.”
“You're right,” Ralph conceded in a voice squeezed flat, his head bent back.
Sam blinked fiercely to clear her vision. It helped a little, enough to see that Ralph stared upward. She followed his lead, and breathed, “No bloody way.”
Stairs reached up, stark and metal, first one flight and then another. No, Sam realized, as her mind grudgingly accepted her eyes' input. The upper flight sat directly atop the lower, an arrangement that made them unusable. Then she noted that the steps of the lower flight were mounted upside-down, with the raised grating underneath. Both flights terminated in open hatchways, through which shone cloud-colored light. Finally, she viewed the upper flight through an irregular hole that sprawled across the ceiling.
But the worst part, the part that made Sam's head want to swim right off her shoulders for parts unknown, was the sight of the tile that covered the surface through which the wrongly-constructed staircase rose, the sort of tile designed to be walked on, not underneath. She was looking up at a floor.
“We're... on the ceiling.” Ralph's voice sharpened in pitch with an attempt at denial.
Sam looked around them, at the conduits in their steel brackets than ran across the concrete in a manner which no engineer would ever consider safe, the lights jutting upward that she had first mistaken for tables. Blood glinted on one of the conduits, and a shard of memory made her wince: the hard plastic tube grew larger in her vision, before the world shattered in pain and went out. Doors sat shut and out of reach at each end of the room, their edges flush with the floor overhead.
Her eyes fell on the hatch nearby, which streamed dingy light onto the topsy-turvy scene. On hands and knees Sam picked her way between the pipes and lights until she gained the edge, and looked down. Grey clouds swam across an endless skyscape, and shadows winged their way through the clouds.
“Where are we?” she voiced the question, but could not honestly say she wanted an answer. Fresh vertigo made the world sway to and fro.
“Quantum tunneling,” Ralph replied, as he made the effort to stand and walk over to join her. “The question may not be where, but when or how many.”
“I'll leave the theory to you physicists,” Sam scoffed gently, “until you can tell the engineer what you need built to sort it.”
“Weird,” Ralph's tone took on a distracted slur as he once more looked up, “the shape of the hole, and the duplication of the room, almost make it look as if there's a puddle on the ceiling, reflecting everything but us.” He limped between the conduits to the upside-down stairs, and mounted the steps. He crouched as he reached the top, cramped by the narrow angle which should have been the underside, and fished in his jacket to withdraw a pen. His face strained in pain as he braced himself with his good arm, and reached the injured one up toward the gap, one end of the pen gripped in his fingers. As he touched it to the gap's edge, the pen snapped in two, and the loose part shot upward to clatter against the far ceiling.
“Thought so,” Ralph grunted.
“Thought what?” Sam demanded.
Ralph leaned over the edge of the staircase, to offer her the broken pen. “Don't touch the edge,” he cautioned, “it's sharper than any razor.”
Sam gathered her feet under her to experiment with standing, and accepted the piece of pen. “It's not broken at all!” she cried. “Looks like it was--”
“Cut,” Ralph interjected, as he levered himself upright to climb back down the stairs. “It was. Sliced right between the molecules.” He chuckled, then moaned as his motion jostled his arm. “We're lucky it didn't hit any atoms, or all of our problems would be solved.”
Sam gaped upward at the gap and asked, “Is that a quantum interface?”
“It is,” Ralph confirmed, as he took the remains of the pen from her and tossed it through the open hatch at their feet. “A breach in the barrier that separates two quantum levels of reality. What Project Allspice was built to achieve, though,” he frowned at the scene around them, “Not like this.”
“I remember a klaxon,” Sam mused, “and everybody scrambled. The lot of us were running up those stairs,” she pointed at the upside-down flight, “then...” She looked up at Ralph. “You ever have a chair pulled from under you?”
“Yes,” Ralph confirmed with a smile, “by you.”
“Oh,” Sam recalled the incident, “right.” Her grin brought color to her cheeks, and her head swam just a little.
“I remember,” Ralph continued, “that's just how it felt.  Like something pulled the world to one side, and we fell off.”
“So what happened to all the rest?” Sam wondered.
Ralph pondered the question, and his face grew somber. “We were at the back of the crowd,” he recollected, “clear of the hatch. Everybody else....” He nodded at the aperture.
Sam stared at the skyscape with its writhing shadows, and understanding tied a knot in her stomach. As if to underscore Ralph's point, one shape soared close enough to break through the clouds, and wind blasted up through the hatch as it passed, huge and dark and something like a dragonfly, or a manta ray, or a jellyfish. The gust struck her hard enough to stagger, and panic made her hands shoot out for any kind of support.
She grabbed Ralph's arm, the one she had offered to set back in its socket, and his scream made her recoil. The room tilted again, but this time it was not only due to concussion-induced vertigo. Sam felt her boots slip on the hatch's edge, and her eyes caught Ralph's as he lunged forward, heedless of his own injury, to catch her. He succeeded, but her balance was too far gone to regain.
Sam caught a glimpse of the room's exterior as they fell. A fragment of the underground labyrinth that housed Project Allspice floated in the sky through which they plummeted, as if some giant had plunged a shovel into the earth and pulled the chunk free. Then it vanished, and only the clouds and wind and shadows surrounded them.