Well, the first two answers (183 & 184 ) do seem logical and indeed conclusive, but I still wonder what the P1 was thinking when he posed the question “You alright?”.
We, all know that we can break an airliner with the elevators, the reaction in pitch is almost instantaneous, giving a very clear feedback via g-forces. However, the rudder is quite different and perhaps more subtle in the nature of such feedback, but it is still there--and a fundamental part of flying. I just can't understand these wild excursions of a control surface only bringing and almost rhetorical question from the P1.
I realize that the resultant tail-wagging could have been misidentified, just adding to the confusion, but surely, most competent PNFs, would have an awareness of the actual pedal movement. Perhaps it's ‘bad form' for a young co-pilot to hover over the captain's controls, but as a captain in these conditions, I know I would have had a tactile awareness of the pedals. Under the circumstances, it sounds as though it would have been difficult not to have. Perhaps by the time it was clear to the captain, it was too late.
It's as though a small paragraph has been omitted from the story: just something does not add up. But then, come to think of it, this is probably true for more than half the accidents that I have read about in the last 45 years.