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.
(Spoiler) Strahm is killed by the walls of the final room crushing him. However, in the original script, rather than the walls crushing, the room was supposed to fill with water, thus mirroring that trap that nearly killed Strahm in the beginning of the movie. Due to practicality reasons, this idea was dropped, though it does explain the air-tubes coming of the glass box. (Which would have been for Strahm to breath.)