I saw it (R was Triplette). It appeared he did not even realize the Tenn player was missing a helmet. Dallas was not trying to take advantage of that. They were in a hurry up mode. The defender knew that so hustled to get on his side and did not worry about retrieving his helmet. At some point Triplette looked behind himself and saw the helmet on the ground. He went to it, picked it up, and then shut things down. If memory serves he then did not have the clock restarted until the snap which was a good move.