You've got to remember that the 737 is almost impossible to fly in a mis-trim situation. It will take one - possibly both - pilots all their strength just to have the aircraft in a vaguely flyable state.
So you follow the memory items on the stabiliser runaway checklist, then discover that you can't trim manually due to aerodynamic forces on the stabiliser. Rinse and repeat. There's a way of dealing with this situation but it's never been taught to you and removed from the manuals 30 years ago.
How much mental capacity does this leave for troubleshooting? Not much. Despite the adrenaline your physical strength is starting to wane. You try to enable the electrim trim. Even during this brief moment the computer aggressively runs further nose-down trim input and makes the situation worse.
It's a brave person that looks at the available evidence here and gives themselves the role of Judge Judy and executioner,
Biting the hand that feeds IT
