As I read situation K, we handle each runner separately. R1 (on third) cannot score because of the interference, so they are returned to 3rd. In the situation presented, F2's throw is errant, so we must judge whether R2 would have been out on a 'true' throw. If so, R2 is out. If not, R2 is returned to 1b.
Now, since in the situation presented here the throw retired R2, he is out. The assumption I make here is that in situation K, since the throw was errant, time is immediately called. Had the throw been true and retired R2, this would be a delayed dead ball. However, in any case, R1(on third) is returned to third.
