And here she thought reincarnation was supposed to be a good thing.
Many people would be very unsurprised of the fact that a jar, especially one with the ability to continually loop time, wouldn't mix very will with a Stupefy spell. Hermione Granger is one of those people. What the event causes, though, is a little more than just a big surprise.
When one is left alone, the mind tends to wander off to the darkest of thoughts. Harry really thinks he should have realized this sooner. Much sooner.