Bleve,
And my belief is that when the crew started to fly manually they might well have found themselves having to cope with the 'yo-yo' manoeuvres described by Centaurus in a previous post (I quote him in italics below) while perhaps also being distracted by multiple warnings as described in the recent Boeing bulletin.
"Excessive air loads on the stabilizer may require effort by both pilots to correct mis-trim. In extreme cases it may be necessary to aerodynamically relieve the airloads to allow manual trimming."
To relieve airloads, the crew must momentarily release all backward pressure on the elevator then rapidly wind the stabilizer trim backwards manually or electrically. In turn, this allows more effective elevator control. In other words, a yo-yo manoeuvre. The crew needed to react instantly and correctly to relieve air loads in this manner. Unfortunately, the Lion Air crew did not have the altitude to successfully recover before impact.
If that was the case, I wonder how well many of us would have coped in that situation.