Yoshida didn't close his palm. And thus the brainscan showed that the Arbiter didn't say the whole truth.
After he saw the scan, Yoshida didn't turn his head back to Jim. He sighed and slowly loosened his tie before standing up and moving slowly to his prisoner. His expression was much darker this time, his wrinkles and imperfections of his face much more visible. Next to the Arbiter's ear he whispered but loudly enough for all to hear.
"Did you really think that mixing a story with some half-truths would allow you to cheat? I thought you realized the situation here. Do you see those marks, Jim?" He coldly asked pointing to the scratches in the walls.
"These are being willingly made by the prisoners at their 9th day of sleep deprivation. In fact this room contains some more interesting marks which you will have all the time in the world to find out if you lie to me again. The alternative is to get back to your normal life, Jim. To your family. Think about it." A suggestion which sounded so normal as if this was a friendly conversation. The Hacker then moved back to his original position.