How do you know they didn’t know he was a felon? Seems like it would have turned up in the ID check. She may have wanted him out of the vehicle to keep him away from concealed weapons.
Easy:
Neither officer was performing ‘cover’ and nor had their weapon drawn after he became combative and the taser failed to subdue him.
Bottom line is that the tragedy underscores their deficit in training. For example, watch the female officer closely before backup arrives (she was FAR too loose).