pardon my newbie ignorance, but -why not check a compass? If not turning and still flying, decending safely shouldnt be out of the question.
Having said that, we in Oz arent permitted cloud flying (bless the lucky poms, though) and although I have ventured into what looked, sounded, felt and smelt like cloud, it wasnt, because that would be illegal here! I was VERY nervous doing it, with that simple lack of vision, and can understand how easily the accident would occur if the pilot was also at the extremes of speed & altitude already.
Is it possible to get a first hand account from the lucky guy and post it for us?

Damn the gravity, Wayne