AZR RE: "Unprotected". In STALL (Alpha), was my meaning. 'G' protection is assumed. The THS was inhibited from TRIM whilst the 'g' was out:
-0.75/+1.25. Is this not why the THS rermained at ~3 degrees on the way up? (zoom climb). Then, after 'g' re-entered -.75><1.25, the THS started to chase 'G' from inside the fence? Concurrent with STALL, of course, and that is the rub?
So, may we see it this way: that THS was dormant whilst a/c was 'maneuvering' (climbing, "bucking"), and it travelled NOSEUP MAX not only to follow elevator, but to prevent 'g' 'negative'? Perhaps a fine point, 'WHY' the THS did what it did, but there remain those two possibilities?
I think it is important to consider that though the pilot appears to be in Thrall with PIO, there is a PIO that can occur in reverse. Specifically, PIO induced 'Turbulence'? Seen it, done it.