It was, she realized, the same discipline she'd learned in the storage room with the abandoned electronics. When a robot behaved unexpectedly, you didn't panic. You observed. You narrowed the variables. You asked: what do I know for certain? Belt secure — yes. Feet flat — yes. The plane is designed for this — yes. Her body said otherwise, but her body was a faulty sensor right now, reporting panic where the instruments reported routine. She'd learned to distrust faulty sensors. She could learn to distrust this too — not by ignoring it, but by checking it against what she knew.

Marisol's hand was warm around hers. "You're doing great," her aunt murmured. "Just keep breathing."

"In for four," Lena whispered, "out for six."

"That's my girl."

Lena shifted her gaze. Marisol's face stayed steady. The plane jolted again, harder. A suitcase thumped in an overhead bin. The cabin lights blinked.

The captain's voice came over the speakers. "We're in rough air. The aircraft is operating normally. Keep your seatbelts fastened."

Lena knew a plane could handle turbulence, but her body did not care about statistics. She counted her breaths: in for four, out for six. The movement made her feel as though the room had been detached from the world.

A flight attendant near the galley lost her balance and grabbed a rail. Camille called to her, then remained seated as instructed. The crew would not move until the seatbelt sign was off. Lena saw the business traveler reach for his laptop, then stop when the plane jolted again.

A child began to cry. His mother tried to soothe him. The aircraft shook hard enough to make the overhead panels rattle. Lena squeezed Marisol's hand, but she refused to close her eyes. Looking away made the spinning worse.

Captain Cross spoke again. "We've asked air traffic control for a route around the strongest cells. The seatbelt sign will stay on. We'll update you when we're clear."

A minute later, the cabin shifted sideways. A voice near the back cried out. Someone had stood to reach the restroom and was thrown against a seat. The flight attendants remained strapped in, unable to reach them. The person was conscious, but the impact had startled the entire cabin.

Lena's fear sharpened into attention. The turbulence was no longer just a sensation. There was a person on the floor, a crew member calling for them to stay still, and a passenger trying to unbuckle.

"Please keep your belt on," Camille called from her jump seat. "Do not move until the sign is off."

Camille called it from her jump seat with the calm of a person who has said it a hundred times and means it every time, because flight attendants learn, early, that turbulence is not dangerous in the way passengers fear and not harmless in the way passengers hope — it is, precisely, the thing seatbelts are for. The rough air arrived without ceremony, as rough air does: a shudder, a drop that felt longer than it was, a collective intake of breath from forty people who had, until that moment, been reading, sleeping, eating half a sandwich. Lena's body, which had its own opinions about motion, registered the drop before her mind did, and she did what her balance disorder had taught her to do: she fixed her eyes on the horizon line outside the window — the steady line, over the wing, that did not move the way the cabin moved — and she breathed, slowly, the way her doctor had taught her, in through the nose, out through the mouth, counting, because counting gives the body a second task besides panic. Marisol, beside her, put a hand on her arm without looking up from her novel, which was Marisol's particular genius: comfort without commentary, presence without performance. Camille moved down the aisle when the sign allowed, checking belts with her eyes, pausing at Lena's row just long enough to say, quietly, "You're doing great. Keep looking out the window. That helps, doesn't it?" Lena nodded, because it did help, and because being seen — being noticed, specifically, by a crew member who had no reason to notice her — was, after the morning's fight to be recorded, a small restoration. The turbulence passed, as turbulence does, in minutes that felt longer, and the cabin exhaled, and the sandwich paper crinkled, and Lena returned to her code, to the line that read # if sensors disagree, stop and ask, and she thought, not for the first time that day, that a body, like a rover, like a flight folder, is a system of sensors — and that the wisest thing any system can do, when its sensors disagree, is pause, look at the horizon, and wait for the signals to converge.