Trivia

To conceal the ending, most of the actors were not given the last 25 pages of the script. Only the principal actors involved in the sequence knew.

It took four days for four people to replace all of the syringe tips with fiber tips for the "Needle Pit" trap.

The bathroom, which was the main set for Saw (2004), had to be recreated for this film.

Five alternate endings were shot.

Shawnee Smith was pregnant during filming, but kept it a secret from everyone, including the director, Darren Lynn Bousman. Her daughter gave the secret away one day during lunch, but only to Darren Lynn Bousman.