WRT the Spiegel article ... Some statements in the article are incorrect, however, for instance the claim that the pax were held in their seats only by their seatbelts. At a steady rate of descent, the pax would experience 1 G.
True -- once the rate of descent stabilized at some -10000fpm. But shortly before that, they'd actually been climbing, so at some point there was a heck of a vertical acceleration, and for that period the description would likely hold true.
I can only hope that that moment passed quickly, because it must have been terrifying.