Things we can all pretty much agree on:
1) PIT manouvers are dangerous
2) PIT manouvers should not be used for traffic violations
3) The driver exhibited standard signs of following instructions.
4) Whether the shoulder was wide enough to stop is subjective, but a cop will know that many will not pull over on such a shoulder.
Having said all that, even if the cop didn't *technically* break any rules, he clearly didn't exercise even a minimal sense of good judgment, and acted in a needlessly dangerous way.
In any other field of work, being technically right but being wrong in every logical and sensible way would be grounds for dismissal. For a cop who's job is to protect from harm to put someone's life at risk unnecessarily is not only grounds for dismissal but is deserving of charges.