Someone asked him about it at SeaCon and he admitted that after they did the scene with Sam dying, he kept holding Jared and crying after the director called cut. I think he got way too far into Dean’s headspace, something they both said happens a lot. Here’s the gifset of his answer: http://nothingidputbeforeyou.tumblr.com/post/159412400554/sure-jensen-seacon
I agree- AHBL 1& 2 had great performances from both guys but Jensen really hit it out of the park with his scenes. Just amazing.