Ah. They'd have had to "roller coaster" the airplane (pitch up, then move the elevator surface towards neutral [so a net nose down]) to get the trim to move manually [the last step on the checklist]. Repeat as needed until the stab is trimmed within a range where it can move manually in unaccelerated flight.

That's an interesting possibility, which if they didn't know about it (I don't blame them), they may have felt they had no choice but to go "off checklist" and re-engage the electric trim system. I'd expect that would be in the context of "PF commands nose up pitch trim continuously while PNF engages the trim cutout to normal and monitors."

That's a tougher hand dealt the crew than I previously contemplated and if that's what they did, it's one for which I will owe them a retraction.