A trim runaway condition should be quite identifiable on a 737, these clunky trim wheels leave no misunderstanding of the direction and speed of trim at least. However, if the AOA disagree warning was triggered, and this also triggered a IAS disagree warning, it might have been difficult for the pilots to see the causal relation. If they would think that airspeed was unreliable and trusted AOA somehow more (despite the inevitable message), and the pilots would think that indeed they were approaching a high alfa condition, it would explain why they didn't intervene in the nose down trim by selecting the cutout switches.
Really hope the voice recorder will be found.