"Greta Salpeter, you will never be a stern professor, so you should drop that act right now before someone less kind than me calls you out on it.. Also, I know just how many times you ended up in detention in fifth year alone so don't you dare try and land me in detention." Z paused. "Actually, I'm not even sure how that would work with me."
Z finished putting things away and brushed her robes off. She wasn't quite sure how to handle this development, bravado had gotten her this far but Greta was still a professor. Which was bloody well strange to think about, because it was Greta. Greta could be an excellent teacher, but Z's always figured that if Greta ever started teaching they'd both be out of school. And Greta might have been teaching an academic subject. And that she certainly wouldn't be considering giving Z detention.
"I'm not actually stealing a broom in the usual sense of "steal." I'm borrowing one. One of the non-school ones, even. It'll totally get returned and in really good condition. So it's a win for everyone; I get to fly, someone gets their broom polished and the twigs clipped and such. It's an excellent system. If someone was going to fly my broom and then take care of it, I'd be completely in favor of this happening."