"I don't mind," Severus answered with a slight shake of his head. And he really didn't. Brewing would allow him to take his mind off this godawful music for a bit, and it would help him to relax as much as he possibly could in the circumstances. So he really didn't mind at all. Quite the contrary.
He gave her a small smile and a nod when she said she would simply pop 'round later to retrieve the potion. It wasn't as if he had anything better to do than hole up in his room, anyway. "You know where to find me," he answered then, with a slight shrug. Then, before she could scamper off, he added, "Good luck with the charm."