I think screwing up Hidan's ritual is going to come back to haunt Shikamaru. The reason I beleive this is what we've seen of Hidan and how he regards his faith and his ritual. Hidan himself stated that he his deeply religious. We've also seen he is very defensive of both his faith and ritual. Look at how he reacted when Kakuzu suggested that he cut some parts of it out. He got pissed off and claimed that would be blasphemy. He confirmed these thoughts even more when Zetzu showed up. Even the recent chapters have shown this. He absolutly refuses to even let Kakuzu do anything since he considers them part of his ritual. Twice he's told him to back off. I beleive in the next chapter Shikamaru will succeed in freeing Asuma from Hidan's jutsu but that by doing so he's going to set Hidan off big time. If you've ever watched the news you've no doubt seen what happens when you do something considered blasphmous to a religion.