Quite a change for a young dressage horse!
You might notice Pat using lots of partial disengagement to help that horse relax.
For any horse, foundation before specialization is important, and foundation must include a wide variety of exposure and experiences to produce a confident, knowledgeable and well rounded partner. Dressage is a sport originating from a purpose (war), but is now solely focused on principle. Hence the importance of rounding out the foundation and training.
My horses have been on trails, on cows, jump, know the dressage basics, swim, play with Doma Vaquera, drive on long reins, spin, roll back and stop, and drag things! I learned the importance of training a versatile horse during my long studies at the Parelli ranch.