Q gives him a silly sort of 'guilty as charged' grin. "You weren't my only teachers Severus," Q reminds him gently. "Though I didn't do any potions work after I left Hogwarts. As I mentioned," he continues, "to defend against different types of magic, you have to learn about different types of magic. Eastern magic, indeed the lifestyle in general, emphasises colour far more than we do. A holdover, no doubt, from Victorian times," Q comments dryly.
Q nods his understanding and listens closely, then quietly takes up his pen and writes as Severus speaks. He looks relieved at the explanation, though he goes a bit goggle-eyed at the mention of ten years.
He stares at his notes. "Yes, I was sharp. I think, under the circumstances, that I can be excused that. I had no way of knowing, or even expecting that I was dealing with a Sirius Black different from the one I knew at school. And I'm certainly not going to apologise for associating with you. Not to anyone," he adds firmly. "Pettigrew, that's right." He shrugs. "A mouse then. Something from the class rodentia. No offense to him. But not a squirrel."
Q listens, expressionless, though his lips do twitch slightly at the raccoon remark. "I swear Severus," he says solemnly, "that if I ever decide I need to embark on a ship of vengeance, I shall do so for myself and for my own reasons. I would never cause you sorrow or pain. Not willingly," he adds. "Not if I could help it." Guilt, anger and frustration skirmish briefly on his face. He muses for a time. "Constructively," he says. "Do you think I could persuade Professor McGonagall to teach me the animagus transfiguration?"
I'm sorry. *pets* I (and Q!) certainly didn't mean to upset him. Woe!