takata:
On the other hand, switching to ALTERNATE would also reduce the MMO limit displayed on PFD down to Mach 0.82 (putting the limit much closer to their real airspeed)... hence, what if the pilot saw that gauge high limit moving close to its airspeed, if it was actually rightly displayed? Could he interpret the warning being an "overspeed" instead of "stall" (even if voiced)?.
Very interesting point, if the PF was scanning the "gap" between MMO and speed more than absolute values he may well have perceived a jump in airspeed when ALTERNATe mode was entered rather than the drop in MMO.
Pity that one very relevant parameter (PF arispeed display) was not recorded on DFR.