Once in a while stick shakers go off, it does not mean you are stalling, merely close to it, or a false warning (as in this case) even a gust can set it off.
Had it go off a couple of times in the 727 over the years, usually on a heavyweight take off at high altitude, Mexico City for example.
Max power and lower the nose a smidgem, and fly out of it.
To put it down again is unthinkable, no matter how much runway is left.
'Hobsons choice !' This incident was in an L1011, one of the best engineered
jet transports ever made, no reason whatsoever to think disaster is at hand.
It certainly did not help that the FO 'gave up' at a critical moment, but the aircraft was flying and they should have kept it so.