Hermione's trying to study for finals. Currently she's going over her Forensics notes and deciding that this is kind of really disturbing when that's all she's reading.
She's kind of grateful when she hears the owl pecking at the window, and then she realizes it's an owl at her window, and not one she recognizes. Either Ron and Harry have had to be more careful, or it's an official one. She's been waiting for a while, and every noise makes her think she's gotten an answer, so she's immediately nervous. She opens the window, and the owl drops the envelope carefully before flying off.
She picks it up with shaking hands- she is that big a dork- and blows out a deep breath. And she opens it.
A moment later there's an "EEEEEEEEEEEEE" noise that scares the cat.