Hidan is definately killing something useless..
Don't forget that Shikamaru said that he would fulfill that role aswell.. I'm sure he means playing the bait for the blood drinking. They prepared for this, so I guess they gave him the blood of a dead animal or something, making Hidan's technique worthless.

I didn't watch the preview, since I like cliffhangers. Even though I know Hidan's going to be fucked.