Sure, Amuro had a place to return to, but...

what happens

Due to Hayate's most recent borderline test scores, Nagi gives him some time off to study. Meanwhile, Klaus sends a robotic butler which looks somewhat like Hayate to fill in for him while he is studying. The robot, known as Thirteen, does an even better job as a butler than Hayate even could, which depresses him when he finds out. Thirteen devises a plan to get Hayate and Nagi alone together, though only Hayate realizes this after the fact. That night, Thirteen goes into space to destroy a meteor heading for Earth, but is stranded on the moon with no power in the process of saving Earth.