B44 intercepts a pass, returning it in bounds close to the sideline. A30 steps out of bounds, punches the football, causing A44 to lose possession. The ball hits the ground in bounds at the A-30, and recovered by A8 at the A-28.
Its clear that a ball in firm possession by a ball carrier would still be live if touched by another player who is out of bounds (AR 4-2-3). And of course, a loose ball touched by a player who is out of bounds would be declared dead.
At what point would the ball be considered not in the player's possession? Would it be the moment the ball is punched, or some time shortly there after? Even though a punch is a rather quick action, its hard to imagine the player still maintaining full control of the ball for the duration of that action.