Massive cloud of debris and pulverized concrete, collectively the matter of upper section of building being laterally thrown in all directions does not allow for the rest of the building to be shredded. You either have plumes of debris spewing outwards and the rest of the building razed by demolition OR you have SLOW pancaking with a great deal of chunked concrete and recognizable tall 'pile' of floors left (with a definite core still protruding and standing thick and tall)..you can't have both.