Mark Sloane needles his son's Captain by suggesting that the mole on his face could be per-cancerous. In neither his previous appearance (The Last Resort (1998)) nor in his subsequent one (Voices Carry (1999) does he have a mole on his face.
When Steve asks to see Maloney's real ID, "your FBI badge", Maloney pulls it out and shows it to him. The problem is, The Witness Protection Program is actually run by the U.S. Marshals Service.