Pretty darn efficient, huh?
Total collapse time: about 6.7 seconds, the same amount of time it would have taken a bowling ball to fall 47 stories. In other words, free-fall speed.
This means the top floor encountered zero resistance from any of the floor or columns below, notwithstanding all that steel and concrete.
If that don't make you go hmmmm, I don't know what will. Let's just vote new powers to the chancellor and forget about it.