Yep, a few years ago agressive use of the rudder was all the rage in the sims here in the U.S. Some of it was in the wake of 737 rudder malfunctions causing upsets. The idea was that using full rudder would speed unusual attitude recovery, which it does if the tail doesn't fail (and you don't get lost and kick the wrong one). I can see where the FO may have got the idea to try to kick his way out of some wake turbulence.