He slowed, the run becoming a trot and then a walk. He walked up to the wall and pressed his forehead against it, looking down the stretch of empty corridor on the other side. He was breathing hard, clouding the transparent plastic. He slammed his fist against the wall—three times, almost fracturing the bones of his hand. He knew he couldn’t break the wall. He hit it to let them know how he felt. Because he knew they were watching him.