Saw IV (2007)

Visible crew/equipment: Several times in the movie you can see a stunt double for Donnie Wahlberg, like when he tries to hang himself. Art runs over and there is a wide shot focusing on both of them. No slo-mo required, but you can see it's a stunt double.

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.

Other mistake: In Saw II, Jigsaw shares a story with Detective Matthews about how he attempted suicide after his cancer diagnosis by driving his car off a cliff. We then see Jigsaw pulling a metal rod out of the left side of his stomach. However, no puncture wound/scarring is visible on Jigsaw's stomach when his autopsy is being performed. (00:00:50)

Phaneron ★

Trivia: When Officer Rigg is walking through the school, before he finds Morgan and Rex in the rod trap, he walks by a dark room blocked off with police-barrier-tape. Originally, there was a scene that revealed this was the room where Troy from "Saw III" died, but it was cut, presumably for pacing reasons.

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.

Trivia: The footage in the beginning of the movie that shows Jigsaw swallowing the wax-covered cassette was actually shot during production of "Saw III", but was not used in the final cut.

Eric Mathews: I don't want to play anymore.

Jigsaw: "Cherish your life" is the motto this whole organization is built on. Cherish your life... your life.

Agent Strahm: We're here to find the person helping Jigsaw and Amanda Young.

Question: A tape recorded by John directed toward agent Perez states that her partner would soon take the life of an innocent man. How did John know that agent Strahm would kill Jeff? For all he knows, Strahm could have followed Rigg through the factory rather than Jeff. The "if you're good at anticipating the human mind, it leaves nothing to chance" excuse doesn't work here. The only reason Strahm followed Jeff was because he heard Jeff hit a ceiling light with a crowbar.

Question: A glass casket with a key inside it is shown in John's warehouse. What does that mean?

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?