And I'd worry this would make Sandoval hate me more but I don't think she cares much about Stretton's opinion. I think she was a lot more bothered that Lucius Malfoy asked her all those questions.

But she hates being made to look foolish. And she already hated him because he made Ravenclaw look just terrible when he got caught selling illegal potions. She might not have cursed him today and she might not do it tomorrow but sooner or later he'll give her an excuse and he'll get no mercy. Maybe he reckoned she'd be looking for an excuse anyway, I don't know.