Could it be that the pull up by the PF was purely to follow his flight director cues that were demanding a pitch up due to an overspeed condition as well?
Could the FD have been commanding a pull up caused by the aircraft sensing an overspeed condition that arose either by the rapid increase of mach no. from hitting the relatively hot air in the top of or leading the top of a very active itcz night time thunderstorm, and/or positive local thunderstorm wind vectors?
I know of two jet aircraft that have lost control in the tops of tropical TS due to being put outside the envelope suddenly in warm TS air at altitude.
And by the way - great post Hundredpercentplease at #1179 - hats off!!