Apparently, according to this discussion . . . "Most complicated: the injury, helmet issue, or foul has to be the only reason the clock stopped."
Since the clock was stopped for the first down, the rule would not be applicable, it would appear. And by logic, a 10 second runoff in that circumstance would usually be excessive, since the ball can almost always be clocked in 2 or 3 or 4 seconds after a first down.