The question is, would LP accept it. If the offer is made formally, and she must present it to shareholders, the share price would almost immediately move to $10, even if she recommended against it. If the shareholders followed her lead, the stock might give up a little, but a $20 bid could follow.
I frankly don't know that Merck would force LP to announce such an offer, by making it official, if she told them she intended to oppose it. I do believe they're working together and when the time is right, she'll agree with whatever is announced as coming from Merck.
Gary
Bullish