THere is also the other three clones so maybe his got a plan to get him distracted and than either trow it or hit him directly with it.
Shikamaru wasted a perfectly good head when he buried Hidan. I know the point of this misssion wasnt to capture one akatsuki for information but I think it was back when they faced them with Asuma. He should of just staved him with a kunai rigth on the forhead and pull out the head, then give it to Tsunade so she can interogate him.

One question for the rest of you. Who do you think is the weakess Akatsuki so far is it Hidan or maybe Tobi?