@Quagsire
The first is that we head right on towards the battle with John McAfee, knowing the dangers that lie in doing so. On phase 9, we can get to the watery ruins and get the second bone of four.
The second is that we take the long road around, missing the battle with McAfee. We would get to the underwater ruins on phase 10, at which time they will have likely have been looted by the crew of the Humphrey's Dream.
At that point, we will be forced into an even more uncomfortable decision - keep on going and get the bone back; knowing that we will most likely have to resort to violent measures in order to do so, given how word of the cruelty of the Humphrey's Dream to its own crew has travelled so far... or we resort to the final road anyways.
The final road I can see us taking is to abandon our current course of action with Barbaros. Find something else to adventure towards.
Wouldn't know what that is.
But hey.
It's an option, Captain.
And I'm behind your back no matter what.