I can understand what has happened, the FO would have activated the rudder trim and would have then been distracted by looking at the aircraft deviating away from normal. That initial confusion was no doubt replaced by panic when the aircraft had a serious 'upset'. It would have been when action was taken to recover the aircraft that he actually 'released' the trim. No doubt had was frozen on there whilst brain tried to process what the hell was going on. I think some recognition could be given to him for actually recovering the aircraft back to 'normal' with out further 'upset'. We have already seen several times in recent history that in these situations a bit of mishandling in 'upset' situations can lead to the loss of the aircraft. Yes he co*ked up getting into the situation but thank god had enough basic handling skills to recover from it. These basic skills are what seems to be lacking in certain areas.