Absurd:

the idea that a 110 story tower could grind itself into a 2 story pile of debris starting with a collapse of the top 10 stories.

Looking at it another way, isn't it clearly absurd that a 110 story tower could grind itself into a 2 story pile of debris starting with a floor collapse at the very bottom? Yet in this latter case, clearly there would be a much stronger "pile-driver" effect. But even in this case, it seems quite improbable that the complete tower would collapse.

Wouldn't you imagine, that if you assume the tower stayed upright, that eventually the energy required for grinding up floor after floor after floor would exceed the potential energy given by the wieght of the upper stories pulled down by gravity?