"Walk and Talk and Aah!" is an orchestral piece from the Season 6 soundtrack.
Jack and Sawyer have been talking about "Locke", Desmond, and their destination - the well. Sawyer asks whether he killed their friends on the sub. Jack says no - Locke killed them - but Sawyer remains unconvinced.
Further behind, Hurley walks with Kate. Hurley notices Jacob in his youthful form, but Kate can't see him. When Kate goes ahead, Hugo is surprised to find the boy right in front of him. He takes the ashes Hurley collected from Ilana's things and then runs off. Hurley chases him and finds an adult Jacob sitting before a fire, which now, as Jacob explains, contains the ashes. Jacob asks Hurley to bring his friends. "The End" is near.
The title references Lost's use of the "walk and talk" - a conversation between characters en route to a destination. Hurley cuts short one of these walks with a loud exclamation when he sees younger ghost Jacob.