Time passed minute by minute, and Keiko was motionless as if she was dead. But in fact, she was secretly observing the movements of the prison guards around her. A total of three prison guards each carried a chair, sat down and stared at her. The three people's perspectives add up to almost 360 degree without blindspot, and all Keiko's actions are under their observation.
However, people are the most vulnerable link. Machines may be foolproof, but humans cannot. The prison guards changed their shift every five hours. At first, they were in good spirits, and they kept staring at Keiko with wide eyes. But after a long time, Keiko didn't move at all, they got bored and began to loosen their minds. However, because the overhead monitor was still in operation, they didn't dare to desert too much, pretending to sit on the chair while actually dozing off.
