“Saw IV” opens with the autopsy of John Kramer, where a cassette tape is pulled out of his stomach. Detective Hoffman plays the tape, which warns that the gory games will continue. Cut to SWAT officer Daniel Rigg (Lyriq Bent) who is forced to play a deadly game in order to find two missing colleagues: Hoffman and, most importantly, Eric Matthews (Donnie Wahlberg) who was thought to be dead after what happened to him during the events of “Saw II.”
A pair of FBI profilers — Agent Strahm (Scott Patterson) and Agent Perez (Athena Karkanis) — trail Rigg as they begin to suspect that he might be Jigsaw’s mystery accomplice. All the while, Bousman pulls back the curtain on the past as we learn about Kramer’s past in a series of flashbacks. Not only does this allow Bell to be in the movie, but it helps the viewer better understand Kramer’s motivations. This is crucial in building a case for the movie’s big reveal. The viewer needs to understand John, just as his potential proteges need to understand.
For much of the movie, we believe that Rigg is being groomed to take over for Jigsaw as his game is all about setting aside his obsession with the killer and, instead, understanding why these people are being selected for the games. For someone to become the new Jigsaw, they must see the world the way he sees it.
Through the flashbacks, we are treated to a thorough lesson on John Kramer’s philosophy. The idea is that John wants people to truly be saved in a meaningful way. Throwing people in prison doesn’t save them. Putting them through social programs doesn’t save them. Killing them outright doesn’t save them. As he sees it, if someone survives when truly faced with death, they will “save” themselves. He wants Rigg (or so it seems) to save the way that he saves.