So what exactly happened here? Clearly they didn't fell down 80 floors, because then they'd be all dead and no elevator cabin to be found. Also, for a cabin to

So what exactly happened here? Clearly they didn't fell down 80 floors, because then they'd be all dead and no elevator cabin to be found. Also, for a cabin to free fall, not only do the cables need to snap but also the automatic brakes need to fail as well. TFA says only two out of many cables snapped. Did the other cables slip, causing unintended cabin descent?