They thought they were diving.
It all started with an unreliable speed, so they didn't trust the speed indicators. In the turbulence they lost all sense of what is up or down. They thought they were not stalled because the stall warning did not sound. When they pushed the nose the stall warnign came up, so that must have made them think that could not be trusted either. Adrealine is rushing and you see the altimeters showing high rate of descent. You think you are diving and pull up. If that does not help panic brakes out and clear thinking stops...