The absorbed life forces are channeled by the male vampires to the female vampire, who transmits the accumulated energy to their spaceship, which is now in over London.
Carlsen and Caine later learn they were deceived, as the aliens had wanted to draw them out of London.
According to interviews with Bill Malin, who plays one of the male vampires, the film went over schedule during production.
Jay Carr wrote in that 'it plays like a tap-dancing zombie'.