That's weird, I could have sworn I did this in my NG type rating 15 years ago
And, likewise, on my Classic rating in the 80s.
A trim runaway is not immediately obvious
Suggest, like most training sequences I have been exposed to (from both ends of the sim), for "trim runaway", read something like "if it's not doing what you want/expect and you can't make it behave" then do something (turn it off) rather than just sitting there staring into space and wondering what's going on ! If, perchance, you over-reacted and jumped the gun, you can always go back a step with this one. A bit similar (if not all that closely related) to the standard TP approach - if you just did something and something unpleasant happens, undo that which you just did and see if the two might have been related.
the aircraft was still grounded for 2 years. Maybe not that simple after all.
There were certification considerations which needed to be addressed. Two different, albeit related, matters.