I believe the 30 second time grab with the a/p disconnect square in the middle would give it up. The Captain has said a climb is not available (I think they were cleared for an eventual Cruise @ FL370). Warm Air. He has also claimed the a/c will (in two minutes time), enter increased turbulence. He is not making small talk. Someone wants a left turn. With an aft load of Trim fuel, one expects at least a slight THS ND to load the HS to lessen Drag (oa). But the THS at handoff is 3 degrees NU.
Warm Air, sink, probably ND (descent)? No big, the Trim is correct, until, Pitots supply discrepant Pressures to AD(s). The autopilot gets out of whack, perhaps attempting a renew of Trim (airframe), and in doing so can't keep up, and for whatever reason, it is disconnected. Now it isn't that important how the Pitots started to read in disagreement, let's assume ICE, though that is not necessary, imo. ICE is patent in UAS, so we go with it. How much has the nose dropped since the beginning of the Temperature change? Unknown, but why would it be less? The a/p (and a/thr) are about trim, so let's say increase in Thrust and a notch more of NU.
The a/p quits, Cavalry Charge, and Master Caution. "I have the controls" says PF, and so he does, for he (right away) inputs NU and Left ROLL, one assumes from what he sees on the FD? Now this is a big a/c, and it is Nose Down, accelerating, and may have excess energy, even too much Thrust. At handoff, does the a/c remain at current Trim? That is my understanding, so if the Pilot has to correct, the a/p was unable anyway. So far so good. We don't know if the a/p had a chance to trim speed back to .80M so may be the PF has to think about that at this point also. He just got the stick, and he hasn't hand flown for awhile, and perhaps never after an emergency loss of Autopilot. He's a little aggressive, but quickly relearns a soft hand. Fighting this soft hand might be indicated, though, for he needs to make some corrections to regain the Plan. Did he overshoot Pitch? Was the THS quick enough to retrim the Tail?
If PF maintained NUtrim to slow, recapture altitude 'lost' in the temperature exchange and possible variable and substantial airstream fluctuations (vertical), then to me he's got it right, and the a/c will catch up.
"What's it doing now"? I don't give this sa remark much credence, and I never did. It is, like Dozy said, almost certainly doing what it is programmed to do.
How often is this type exposed to the combination of factors present for this upset? Computers don't 'forget', and that is a good thing. Neither do they 'think'.
The last thing on Earth anyone wants is to not understand the a/c, maybe worse is to misunderstand the aircraft. At least in confusion lies inaction?
For me, I'd like some more data, especially what happened in those thirty seconds. I think the Pilot turned left, and the aircraft turned right. (Metaphorically).