It's not PSK because the foul occurred after the kick ended. I think the "question" here is where the basic spot is. It's a running play where there is no neutral zone, so one rule would say that the basic spot is the end of the related run in the end zone. (10-2-2-d-1-c) But it's also a running play that ends in the end zone after there was a change of possession in the end zone and the result of the play is not a touchback, so another rule would say that the basic spot is the goal line. (10-2-2-d-2-c, 2-17-1-c, 2-4-1-b-3). But it doesn't matter because no matter which spot you use, it is a safety. Whether the penalty leaves the ball behind the goal line or on the goal line it is still a safety by penalty. (8-5-1-b). So, while there might be some confusion about which spot to use, it doesn't matter. The ball is still on or behind the goal line and it will be a safety.