Hypothetical ... Play Along .....?

If the player did not intend to actually injure the referee as a part of his end zone celebration, I dont see how the player could get a penalty flag, Because the referee is a part of the playing field just as anyone else of the field at the time. All I think would happen is an official timeout would be taken to tend to the injured referee. Its almost like the scenario of a running back running into a ref and gets tripped up and falls to his knee, is he down by contact???