Okay, I asked this in the PL the other day, but I'm not satisfied with the answer.
The play in question was a broken play where Kap escaped the pocket, looked as if he was going to take off, at the last second (before crossing the LOS) he passed the ball to Gore, then after a second he took an egregious late hit. The hit was so late it wasn't seen until replay. They showed a replay and Aikman commented quickly that the hit was legal because Kap had declared himself a runner. My confusion is that it seems impossible for someone to be a runner on a play they throw a pass. The rule book states that a QB is declared a runner when they tuck the ball and take off, but it doesn't specify that the player remains a runner when they decide to bring the ball back up to make a pass. To me any time a QB throws the ball, they should be considered a passer. Thoughts?