Who thought this was a good idea?

Fifth year, first class. Aidan was ready for mostly everything. Not only did he catch up with Potions and Defense Against the Dark Arts during summer, he also visited Spain during the entirity of August. The only real obstacle this year was going to be Transfiguration, since he wanted to finish his OWL together with the other fifth-years. But he was confident. He'd asked Walker if he could give him extra classes, and he would be taking the classes with his year-mates, so he'd have to catch up. He looked forward to the year. 

Something that made him very happy was the fact that his first class would be Charms. He was simply the charm-master of the year, and he was ready for everything Boux would throw at him. As he entered the room, he sat down near the far left corner of the classroom, next to some guy. "Hey, I'm Aidan."

The next moment, they were revising charms. As the desk next to them set on fire (again), Aidan extinguished the flames and continued reading through his textbook to see what they'd learn after that. His eye fell on the "Silencing Charm". He pointed his wand to the first idiot he saw who raised his wand way too fast to do anything even remotely resembling a spell, and murmered "Silencio." No words left his mouth, and his wand just waved through the air, doing absolutely nothing. Since the poor guy started shouting without voice, Aidan flipped some pages until he saw the counter-charm. He pointed again and calmly said "Vox." Luckily, nobody noticed, Aidan thought...