The Reasons

Since Magnus held eye contact with the Emperor, his mind has been busy recalling that short moment that he had with his majesty. 

When he turned around and didn't find them, he felt kind of disappointed because he wanted to continue this strange eye contact with the Emperor to see what will happen in the end. He wanted to see that moment when Octavius would divert his gaze away from him for some seconds and then move his eyes back again to look at him but unfortunately, when his father called him, he missed that chance.

Magnus tried his best to just push this out of his head and just think of something else but his mind seemed to not like this idea instead it just kept reminding him of that moment every now and then.

A loud sigh came out of Magnus' mouth as it was after midnight and he was still washing the dishes of dinner that he had with his father who had already fallen asleep in his room more than two hours ago.