20 Things You Didn't Know About Saw
15. The Shotgun Trap Was Meant To Be Completely Different
When Sing and Tapp chase Jigsaw down a hallway, Sing activates a trap when he passes through a trip wire. The wire is connected to the triggers of four double-barrelled shotguns which are attached to the ceiling. When Sing passes the wire, the guns go off, blowing his brains out.
Considering how creative the traps are, this one seems pretty mundane by comparison. Why didn't the creators think of something more creative?
But here's the thing. They did. According to the audio commentary, two hidden metal plates were supposed to appear from the walls after Sing passed through the trip wire. These plates would then trap Sing inside a device which worked similar to an iron cocoon. They plates would close in, crushing Sing to death. An alternative idea was for the trip wire to activate a Rack Trap that would slowly stretch and break Sing's limbs.
The director realised he didn't have the time or the money to set up such an elaborate device and so, settled for the Shotgun Trap instead. The Rack Trap was repurposed for the ending of Saw III.