5.17
After that horrible deed he did to Mamoru, Sakuma halted all his projects and solely used W41-FU to monitor Mamoru's activity remotely. He told W41-FU to give him news whenever there was a change in Mamoru's normal activity or whenever there was a change in Mamoru's memory.
Although Sakuma was confident that his perfect android wouldn't realize that he was an android, because he completely mimicked what a normal human would do. Even if Mamoru went on X-ray, it would still show a human organ, unless Mamoru went under surgery, then that was inevitable.
Honestly, Sakuma still hated the fact that Amano-San cared a lot about Mamoru. Truthfully, all he wanted was to just destroy this android, and then go on with his real plan. But when he faced Amano-San who smiled at him and rubbed his head, he felt weak.
Whenever they were together, all he wanted to do was just spend time with Amano-San. He wanted to forget all his horrible past, and stayed with Amano-San forever.