Squall sighed, he wanted to simply forget the explosion and the silver-haired person, however he couldn't allow his stubbornness place the students in harm if it came to that. He waved his hand over the board, and what were apparent notes appeared, "I do not care how you learn this, but learn it. There will be quiz on it tomorrow. While I am gone, stay in your seats. If anyone else leaves the classroom, they will be expelled." he then turned his head to kid that apparently did not want to be hear, and addressed him directly, "While usually I would glad expel a person like you, I have more important things to tend to, and if you leave this room, I will think of something far worst than being kicked out of this school, and you will not get the excuse of not showing up here." he said, angry but clearly not at the student he was talking to. "Now, if you would excuse me."

Perhaps unexpectedly, or perhaps not, he teleported out of the classroom and towards the obvious cause of all this mess, the nearby site of the explosion, whenever he got there, he recognized the person from the classroom who clearly was not an actual student, though this did confirm it since what used to get out of class was way more advanced than simply teleporting, which was already quite advanced. 

He turned his head towards the silver-haired person, "What are you doing here, and what was you doing in my classroom. You clearly was not, nor are a student."