Well if this is the case with what Stevens and those with him were doing, then they have a little responsibility for going off the books too. Don't forget that aspect, if this is true. If that's the situation they willingly put themselves in? If true, they didn't go into it blind not knowing the risk.
And if this is true, it raises good questions on who targeted them. If this story is correct, could have been Russian or Syrian assets who were pointed toward taking them out.