Minutes after Amanda Young (Shawnee Smith) leaves him in the underground bathroom at the end of Saw II, Detective Eric Matthews (Donnie Wahlberg) escapes by breaking his foot with a toilet lid and slipping it out of his ankle chain.
Six months later, another Jigsaw victim is discovered by Lieutenant Rigg (Lyriq Bent) and Detectives Kerry (Dina Meyer) and Hoffman (Costas Mandylor). In his test, Troy (J. Larose) was to rip chains from his body in order to flee from a bomb; however, the door to the room was sealed, making the trap inescapable and thus going against Jigsaw's methods. Kerry, who feels guilty over Matthews' disappearance, later awakens in a harness hooked into her ribs. A key to unlock the device is within a beaker of acid; though she retrieves it, the device still tears her ribcage apart in opposite directions, making her trap inescapable as well.