Doing what the police say in this case would have meant exposing a patient to a deprivation of his Constitutional rights (with potentially no recourse) as well as an arrest record.  It also would have meant there was no dramatic body camera footage to call attention to this abuse.  That would be the difference between an investigation into this officer and him continuing to violate the Constitution.  It could also be the difference between needing a lawyer to fight the charges and getting an apology from the department.