Tunnels 02, Deeper

that on the other side of the door would be an air lock, then a final door, and then the Quarter.
    This was it, the final step: If she crossed through that air lock, she was back, and well and truly in their clutches again.
    His ankle-length leather coat creaking as he moved, one of the two Styx stepped into the light and took the edge of the door with his thin white fingers, pulling it back so that it clanged against the wall behind. No one spoke as the sound echoed around them. The Styx's black hair, drawn back tightly over his head, had traces of silver at the temples, and his face had a distinctly yellow hue to it and was deeply wrinkled. There were such uncomfortably deep creases on each of his cheeks that it looked as though his face were about to fold in on itself.
    Rebecca was watching Sarah, waiting for her to enter the air lock.
    Sarah hesitated, her instincts screaming at her not to go through the door.
    The other Styx was more difficult to observe, as he remained in the shadows behind the girl. When the light did catch him, Sarah's first impression was that he was much younger than the other man, with clear skin and hair of the purest black. But as she continued to look, she could see that he was older than she'd first thought; his face was lean and drawn to the point that his cheeks were slightly hollowed, and his eyes were like mysterious caverns in the dim light.
    Rebecca continued to watch her. "We'll go on. You come when you're ready," she said. "OK, Sarah?" she added softly.
    The elder of the two Styx exchanged glances with Rebecca, and gave her the merest of nods as the three of them passed into the air lock. Sarah heard their feet clunk on the ridged floor of the cylindrical room, followed by a hiss as the seal on the second door was broken. She felt the gush of warm air on her face.
    Then all was silent.
    They had gone into the Quarter, a series of large caverns linked by tunnels, where only the most trusted of citizens were selected to live. And a handful of these were, under the supervision of the Styx, allowed to trade with Topsoilers for the basic materials that couldn't be grown or mined in the Colony or the layer below, the dreaded Deeps. The Quarter was something akin to a frontier town, and the living conditions weren't very wholesome, with the ever-present risk of cave-ins and floods of Topsoil sewage.
    Sarah tilted her head to squint into the darkness of the elevator shaft above. She realized she was kidding herself if she thought she had any alternative. There was nowhere to run. Her destiny had been taken away from her and placed in the hands of the Styx the moment she'd taken the knife from her throat. At least she was still alive. And what was the worst they could do? Kill her, after they had subjected her to one of their more horrible tortures? The outcome would be the same in the end. Dead now, or dead later . She had nothing to lose.
    She swept her eyes over the elevator cage for a last time, then started toward the dusky interior of the air lock. It was approximately fifteen feet long and oval in shape, with deep corrugations along its walls. Using the sides to brace herself as her feet slid on the greasy metal furrows beneath them, she slowly stepped to the open door at the other end, her apprehension mounting.
    She leaned out. She caught the abhorrent language of the Styx -- reedy, staccato words that ceased as soon as the trio saw her. They were waiting a little distance away on the other side of the large tunnel. As far as the light in Rebecca's hand permitted Sarah to see, the tunnel was empty, with an expanse of cobbled road and then a strip of stone pavement where Rebecca and the other Styx stood. There were no houses; it was a highway tunnel, perhaps connecting to one of the warehouse caverns that were dotted around the periphery of the Quarter.
    Slowly she lifted one foot, then the other, over the lip of the air lock doorway and planted them on the shiny-damp cobblestones. She couldn't believe she was actually back in the Colony. She hesitated. Glancing over her shoulder, she looked at the wall that swept up in an elegant arc to where it would join the similarly built opposing wall, although the apex was obscured from sight in the gloom. She reached out a hand to touch the wall by the door, pressing her palm against one of the huge rectangular blocks of precisely cut sandstone. She felt the faint thrumming from the massive fans that circulated air around the tunnels. So