Pumpkin probably should have been more aware of her surroundings ⁠— although who would be looking on roofs? — if she really were worried about vampire attacks. That said, she was surprised when a rock was thrown at her, knocking her wand out of her hand (which, really, she probably should've had a better grip on it).

The former Ravenclaw tried seeing where her wand had landed, but couldn't see it in the darkness. After a few seconds, she glanced in the general direction of where the rock had come from.

There was no way that it'd just been an accidental throw, so who was assaulting her and why?