Their argument isn't with you or me. Greening's and Bazant's argument is with Isaac Newton.
I have shown how Newton's laws are respected by the Baznt model if we look at things in terms of conservation of momentum rather than Newton's third law. Since Newton's third law is derived from the principle of the conversation of momentum, we effectively show that the 3rd law is respected as long as momentum is conserved. We have seen that Bazant and Greening's work does deal with conservation of momentum (remember our discussion of concrete pulverisation?).
Therefore, there is no conflict between Bazant's work and Newton's work.
Well no because Newton's laws state that the energy required to deform and break through the first floors, and the conservation of momentum in the acceleration of the upper floor of the lower block due to the descending upper, would cause a significant reduction in the negative velocity of the upper block. In fact what happened was that the upper block never decelerated through the collapse. The upper block continued to accelerate until reaching constant velocity.
Bazant and Greening are trying to pull the wool over your eyes. And it appears they've succeeded.