The problem I see with them giving less value to shareholders is the lack of a valid reason for them to back out of their original commitment, which is to have the $600 million convert at $4.00.
They can always go back and offer shareholders $0.20 per share and try to get them all out of the picture, but I see it as unlikely that a $14 million payout (that's the value at 20 cts) would silence all people involved. I have read studies about the "nuisance value" of worthless stock, and in this case with deep-pocket controlling shareholders I can see it at 5% of total value (i.e. the $600 that MM/CC invested), which comes to about ... $0.50, or $40 million.
The board, in any event, could be liable if they make decissions that favour some shareholders at the expense of others. A sale to a third party now that nets current common shareholders $0 would be taking away the option value of the stock in exchange for a current payout to MM/CC that they have little or no claim to from a purely legal perspective. Tough situation for the board, but they probably don't want to face another shareholder lawsuit.
Hope the above make some level of sense to you.