Mark, I'm sure the Navy was, in no way, negotiating with the 4th pirate/terrorist. They were using the "divide and conquor" tactic. I'm pretty sure, that once he was on board the Bainbridge, they also offered to trade him back to the other 3 in exchange for Capt Phillips....
Those were very tricky shots, whether they came from the fantail of the Bainbridge or from the Seals in the water. The pirate/terrorists are now threatening to retaliate.... As Dirty Harry said, "Go ahead, make my day" or, "How lucky do you punks feel today!"
The French apparently rescued some of their citizens from a captured sailboat on Friday, killed the terrorists but also lost one of the captives while freeing 4. Didn't make much of a wave in the press in this country though.
Too bad the place they are operating in is so darn big. Very difficult to cover. Sure would help if we had John Lehman's "600 Ship Navy" instead of the 283 or so that we now have.
Charlie