When the camera moves from Troy's crime scene to Kerry being in the bathtub, that was all one shot - Dina Meyer had to run around the set, take off all her clothes, and jump into the tub. If you look closely, you can still see the water moving from when she got in.
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There is a far-away shot when the first pig comes out. You can see Jeff standing on the platform holding his left hand to his face, there's an instant cut to a close-up of Jeff, but now his right hand is held up to his face. See more...
When the camera moves from Troy's crime scene to Kerry being in the bathtub, that was all one shot - Dina Meyer had to run around the set, take off all her clothes, and jump into the tub. If you look closely, you can still see the water moving from when she got in.
In the first scene of the film, Detective Matthews is trying to get the gun. When he looks around the room, seeing Adam and Zepp's bodies and Dr. Gordon's foot, we also see Xaiver's body, which is not a dummy, but a cameo made by Franky G.
During the brain surgery scene Jigsaw relives a romantic scene in a park, during one of these shots you can see the character Obi who was burned to death in Saw II.
According to the Saw III commentary, in a flash back of Jigsaw and Amanda setting up the bathroom trap, Jigsaw told Amanda to tie the key to Adam's foot, making the trap escapable. However, Amanda was careless, and instead just tossed it onto Adam's chest before leaving. Because it was unattached, it was then sucked down the drain as he woke up.
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