Lost: Series 5 Episode 1 - Because You Left

Faraday bangs on the hatch door and is confronted by Desmond in a yellow protective suit. Desmond does not know who he is and points a gun at Faraday.
He tells Desmond that he special and that the rules don’t apply to him but also that the people who were left behind are in danger, he instructs Desmond to go back to Oxford where they met and find his mother, but before he can say her name there is another flash and he is gone.

Desmond wakes up next to Penny on their boat. He tells her he was back on the island. Penny tells him that he has been off the island for three years now and is safe. Desmond is adamant that this was not a dream but a memory. He runs above deck and releases the anchor. Penny asks where they are going. Desmond replies, “Oxford”.