Jigsaw: Hello, Agent Strahm. If you're hearing this, then you've finally found what you've been looking for. But is the discovery of my body enough? Or will your insatiable hunger to uncover the truth push you deeper into the abyss? Heed my warning: do not proceed. For this room can either be you sanctuary, or it can be your grave. The choice is yours.
Agent Strahm: Fuck you.
When Seth has been sliced by the blade, he spits blood that goes all over his face. It then cuts to Hoffman looking at him, then back to Seth, and now the blood on his face has gone. This happens three or four times.
The coffin trap at the end of the movie, in which the walls move in, is based on a drawing done by director David Hackl's young son. (DVD extras)