Creative Speculation

Now you're actually citing a different paper (the addendum published in March), but whatever.

What this says, literally, is that the fall takes longer than a free fall. Really, that ought to be enough.

In context -- as you presumably noticed, since you copied the section title -- the topic at hand here is whether "the inelastic deformations of columns, analyzed in Appendix II of Bazant and Zhou (2002), might have significantly 'cushioned' the initial descent of the upper part, making it almost static." The conclusion is: no, the inelastic deformations couldn't significantly cushion the initial descent. That's relevant to Bazant and Zhou's topic, which they cleverly tuck into their title: "Why Did the World Trade Center Collapse?" Bazant seems to have become more interested in the timing question later.