"They've been given Sympathetic Blocks. You know about SBs, girl? Intelligence uses them for espionage agents. Take a certain body of information you don't want told. Link it with the sympathetic nervous system that controls automatic respiration and heart beat. As soon as the subject tries to reveal that information, the block comes down, the heart and lungs stop, the man dies, your secret's kept. An agent doesn't have to worry about killing himself to avoid torture; it's been done for him."