 When Jason and Gwen are following Brandons directions to escape  through the ships ventilation system, Gwen says, "Ducts. Why does  it always have to be ducts?" This is a reference to  Sigourney Weaver (qv)s character Ripley in the "Alien" movies. It  is also a variation on the famous Indiana Jones line: "Snakes. Why  does it always have to be snakes?"