I looked at Thorne, really looked at him, past the stethoscope still hanging around his neck.

He was not a doctor who happened to be on board to help.

He was the clean-up crew.

The airline had known Captain Pierce had the safety files.

They had known he was going to deliver them to the aviation authority in London.

“The cabin air systems,” I whispered, the puzzle pieces locking into place.

“They’ve had bypass valves failing on this fleet for eighteen months,” Thorne said.

He did not sound angry; he sounded like a man reading a spreadsheet.

“Owen Pierce wouldn’t let it go.”

“So you poisoned him,” I said.

“The toxin is tasteless, odorless, and delivered via the crew’s designated oxygen supply,” Thorne said.

My hand flew to my collar, remembering the mask I had almost used earlier.

“And the rest of the passengers?” Whitmore sobbed from the doorway.

“Collateral damage,” Thorne said.

He did not even look at the businessman.

“An unfortunate, tragic system failure over the cold water of the Atlantic.”

“You’re a monster,” Whitmore screamed.

He lunged forward, but his foot caught on the cockpit door sill.