They sped through the maze of the Habitat, offering strained bland smiles to those quaddies and downsiders they flew past in the corridors. At last, the familiar door to 'Hydroponics D' closed behind them.

"What happened? How did this happen?" Leo asked her as they brushed through the grow-tubes to the far end of the module.

"They wouldn't let me go see Claire day before yesterday, when you brought her back on the shuttle, even though we were both in the infirmary. Yesterday we were on different work teams. I think it was on purpose. Today I made Teddie trade with me." Silver's voice smeared with her distress. "Claire said they won't even let her into the crèche to see Andy on her off-shift. I went to get fertilizer from Stores to charge the grow-tubes we were working on, and when I came back, the lock was just starting to cycle. . . ." If only she hadn't left Claire alone—if only she had not let the shuttle take them downside in the first place—if only she had not betrayed them to Dr. Yei's drugs—if only they'd been born downsiders—or not been born at all. . . .

The airlock at the end of the hydroponics module was almost never used, merely waiting to become the airseal door to the next module that future growth might demand. Silver pressed her face to the observation window. To her immense relief, Claire was still within.

But she was ramming herself back and forth between door and door, her face smeared with tears and blood, fingers reddened. Whether she gulped for air or only screamed Silver could not tell, for all sound was silenced by the barrier door, like a turned-down holovid. Silver's own chest seemed so tight she could scarcely breathe.

Leo glanced in. His lips drew back in a fierce scowl in his whitened face, and he turned to hiss at the lock mechanism, scrabbling at his tool belt. "You fixed it but good, Silver . . ."

"I had to do something quick. Shorting it that way blocked the alarm from going off in Central Systems."

"Oh." Leo's hands hesitated briefly. "Not so random a stab as it looks, then."

"Random? In an airlock control box?" She stared at him in surprise, and some indignation. "I'm not a five-year-old!"

"Indeed not." A crooked grin lightened his tense face for a moment. "Any quaddie of six would know better. My apologies, Silver. So the problem, then, is not how to open the door, but how to do so without tripping the alarm."

"Yes, right." She hovered anxiously.

He looked the mechanism over, glanced up rather more hesitantly at the airlock door, which vibrated to the thumping from within. "You sure Claire doesn't need—more help anyway?"

"She may need help," snapped Silver, "but what she'll get is Dr. Yei."