For Rio management...It literally comes down to these two choices.
1) Explaining to board how they lost a necessary protfilo asset like this or
2) Explaining to the board why they exceeded the "Sooner" 40% premium to current market cap.
My guess is they will go with #2 because this isn't really more than Sooner's metric even if historically that range has been true of the market cap just before the buyout announcement.
Sorry Sooner.