This was the signal to go all in with the steal, IMO. They knew at that time that Trump was going to win big even with the fix they had been going with and they now needed a no holds barred effort to take Trump down. People kept asking who sent the signal to stop counting. I think this was it.
I think Murdoch needed to sign off, but it was Ryan who called him and told them they were fucked otherwise. Ryan also needed Murdoch's pull to get the rest of the MSM on board with the plan.
IIRC, swings states' counting stopped after the AZ call.