Honestly, at this point, Ruby and the cop are the only characters I flat out don't like, so the less of them the better. I really hope Ruby gets informed that it was her Dad's (Raymond Knowby, the unseen professor from the movies who first had the book) stupidity that is at the very core of everything that's happened to Ash. If her Dad hadn't translated the necronomicon and tape recorded what he did, Ash would never have run into deadites in the cabin, and none of this would ever have happened.
Really, while Ash is a (loveable) idiot who definitely deserves blame for some things, like this current deadite investation, Ruby's Dad is the origin of everything wrong that's happened since Ash first visited the Cabin. So, when she keeps complaining about Ash, it gets irritaiting. Same with the cop, who is the sole reason the book seller died and Kelly got possessed.
Also, more specific to this episode and the last few, if Kelly hadn't stupidly released the cop a few episodes back, who then broke the summoning circle, the Demon would never have killed the bookstore owner or possessed Kelly. So, really, when it comes to whose "fault" the demon was, I'd give 20% of the blame to Ash, 40% to the cop and 40% to Kelly for releasing the cop. It was a stupid idea from Ash, but it would have been fine if the Cop had stayed locked up.
The series is still very good, although this episode was probably my least favorite. Too much stupid from Pablo, and the demon wasn't even trying to hide, to the point where it became ridiculous that anyone thought that Ash was the possessed one (specially since ungagging him was all it took to prove he wasn't possessed).