As Ben gets his own grave dug chest deep, he hears the sounds of the smoke monster approaching. Locke appears behind him, out of Ilana's line of sight.
Ben tells Locke what he's doing and that Locke will get what he wants when Ilana kills him. Locke says that he doesn't want Ben dead and that he went back to the four-toed statue to get him. Locke tells Ben that he is gathering a group of people to leave the island for good, but he wants Ben to be in charge of the island when he leaves (a very different story than when he told Sawyer that no one needed to protect the island).
Locke casually waves his hand which releases the restraint around Ben's ankle. He tells Ben to come to the Hydra island which is where he and his group will be. He says that there's a rifle leaning against a tree 200 yards in the jungle and to get the jump on Ilana and not to hesitate, because she won't.
Ben makes eye contact with Ilana, then makes a break for it.
So how much of what Locke said is the truth? Does he hope that Ben will kill Ilana? Does he really want Ben to be in charge of the island? It seems that Locke is telling each person he's manipulating exactly what they want to hear, in Ben's case, it's that someone thinks that he's of value and capable of bigger things.