The dead man's switch trembled in his hand. His thumb lifted.

Hiroko's calculations spiraled. The sociopath was wired to a dead man's switch connected to the gas line. If his heart stopped, the building blew. If he was subdued, he'd trigger it. A logical stalemate.

Then came the fourth. The mastermind. He wasn't a program. The proctors had inserted a live, convicted sociopath for the final test. He had no readable emotion for Oishi to grab onto—a black hole where a heart should be.