Well going with a Pugwash Station analogy, how do you catch a bigger fish in a pond when the fish you have isn't going to be enough? Use it as bait!
My feeling is Stein was looking for a payout (hence the 5 million shares added for MGT incentives), his last company had closed the doors and Pfizer bought some research from them after that, not exactly the payout he is was looking for then. With that said, he got an offer from Cubist before needing the real money of bringing this to market (150+ reps, support staff, marketing....which would equal stock dilution, lower share price and headaches) so instead of countering, he took it thinking if there are other suitors out there, this will flush them out in a hurry.
I don't think this over just yet.
I'm not approving anything less than $16.00 PPS, now if Cubist had been decent enough to just pay the $15.50 now, I could have lived with it, but now, they can burn in hell. Someone got paid on this deal, and the particulars will eventually come out.....