If my theory is correct about the vertical stab failing initially from the front then the rudder inputs by Sten were probably to correct the stab causing the yaw. He was only trying to maintain heading so multiple reverse inputs would be what any pilot would do if the stab was causing severe yaw problems. If you were the captain would you let him thrash the plane around for a common wake turbulence event? I don't think so. Any flight attendant in the back would be severely injured if she was out of her seat for some reason. We all deal with wake turbulence and it is not an emergency, we just have to make that PA explaining how it is like being behind another boat to calm nervous passengers. A lot of politics was in that NTSB final findings.