Right after Charlie tells Hurley that he believes he's doomed to die, Hurley replies that he's cursed—death always finds him. Vincent immediately appears out of the jungle with an arm in his mouth.
Vincent runs off, and Hurley follows him into the jungle. When the dog drops the arm, Hurley examines it and sees it was holding an ignition key with a rabbit's foot attached. He continues following Vincent till he leads him to the DHARMA van.