@oralloy,
I think I answered this question. And the Police Lieutenant answered it better (and he gets to speak to the jury).
The prosecution argument is that even if the knee restraint was necessary to get the handcuffs were on, that it should be released as soon as the suspect was in handcuffs. At that point there is no need for the police to maintain the neck restraint.
The cop makes sure the suspect and the scene are safe. This includes moving him from the prone position and ending any dangerous restraints. Then they have time to get help and to safely move the suspect in a controlled way to the squad car.
That is not what this cop did.
The defense is going to argue that doing this safely wasn't possible. I will listen to the defense argument too.
But from the testimony of this police lieutenant, that I found compelling, what Officer Chauvin did was dangerous, inappropriate, and completely unnecessary.