Saw IV (2007)

Continuity mistake: The blood stain on Riggs' white shirt around the neck has blood under the collar, then at the end it is over the collar and has increased in amount.

Hoffman: Game over.

Trivia: At one point, the producers were considering using a version of the autopsy scene as the final scene in "Saw III." It was then retooled and used as the opening for this film.

Question: I don't understand why Hoffman isn't electrocuted at the end. He was connected to high voltage cages and his feet came under water, so how did he and/or Jigsaw plan so he wouldn't be electrocuted under any circumstances?