1Q 00:40 punt. B muffs the punt in the field of play. Balls rolls into the EZ where B illegally kicks it out of the EZ. I’m pretty sure I know the answer, but I would like rule references to back it up.
The natural result of the down would be a touchback (impetus is with punt). But, the penalty for the illegally kicking of the ball in the end zone (PSK/3 & 1, with PSK spot at the B-20) would result in a safety. So, Team A can accept the penalty, get 2 points, with a free kick to follow, OR decline the penalty and let Team B have the ball at the B-20. In an extreme circumstance, i.e., needing field position to score a TD, Team A might decline the penalty. But, highly unlikely.