It's more like it was "GET OUT OF THE F***ING CAR", being shouted by several JBTs at the top of their lungs.
It's also very possible that another agent was shouting "DON'T F***ING MOVE" to the kid, just to (intentionally) confuse the situation for the victim.
That way, if he didn't move they could shoot him for not "getting out of the f***ing car".
Done properly, the agent would have been behind cover and ordered the suspect out of the vehicle step-by-step. Done properly, the agents would never have been in a position to be worried about a furtive movement placing him or her in fear.
The shoot is bad because the agent ran up to the vehicle and didn't follow proper procedures.