In my prediction, do you remember when Sato visited Mitsuboshi (that boy, who loves Shio and caller her an angel)? I think Sato had something planed with him in order to hide Shio (we have known that he won't dare to betray Sato after all she's done) while it's also good for him as he can meet his angel once more; it's a win win situation. And now Sato will proceed to bring her friend home and it's either put her to sleep eternally or set up another lies. And to explain that guy at the end, you remember this and proceed to read how he reacted to the scene.
