After Hurley loses Dave's trail twice, he asks Sawyer (Josh Holloway) for medicine to fight the hallucinations he believes he's been having.

As proof, Dave points out the appearances of the numbers said by another intern, Leonard (Ron Bottitta) in both Hurley's winning lottery ticket and the hatch computer number-sequence.

Hurley states to her he believes everything happening is not real, and is only a comatose dream, including her, but Libby convinces him otherwise, in part by kissing him.

In the hatch, Sayid (Naveen Andrews) and Ana-Lucía (Michelle Rodriguez) interrogate "Henry Gale" (Michael Emerson).

ABC was concerned about the content of the episode, arguing that the idea that the story could be all in Hurley's head was offering an explanation for the show as a whole,[2] since a recurring theory among the fandom was that the events of the series were hallucinations.

[4] The final scene with Libby was so secret that only Jack Bender and his assistant director had it in their scripts, and to prevent Libby from being the only woman in the mental institution, every woman on the set, including Bender's daughter Sophie, was dressed in robes and pajamas to appear as background characters.

[3] Director Bender decided to depict Dave in a way audiences would first believe him to be real, but without the character actually interacting with the physical world, similar to films such as The Sixth Sense and A Beautiful Mind.

[5] The scene in which Dave starts listing to Hurley why the island events are occurring in his mind suffered from continuous interruption, as military exercises on Joint Base Pearl Harbor–Hickam led to many takes being ruined by plane noises.

Scott Brown of Entertainment Weekly praised Jorge Garcia's and Michael Emerson's performances, and said that the episode made the island "feel dangerous again".

[7] Ryan J. Budke of TV Squad felt that the B-story in the hatch was more interesting than Hurley's scenes, and considered "Dave" depressing, in opposition to the other "so light-hearted" Hurley-centered episodes.