Continuity mistake: When we see the garage trap we see that half the windscreen is smashed away and the other side has a crack through it. However in one shot, the cracks have gone. (00:19:10)
Continuity mistake: When Nina dies, Bobby has her blood all over his face. When he picks his book up a few seconds later the blood is gone. (00:41:00)
Revealing mistake: If you look very carefully when Gibson is machine gunned down, you can see the blood packs in his jacket. Slow-Mo may help but is not essential. (01:07:15)
Continuity mistake: As Evan is tearing himself away from the car seat, you can see his back muscles are a fleshy-color and only have a little bit of blood on them. When he crashes at the end of the scene, his back muscles are suddenly dark-red and saturated with blood, despite looking totally different just seconds before. (00:20:25)
Continuity mistake: At the end of Saw VI, Hoffman has got a massive chunk of cheek missing from the reverse bear trap. However in this film, which continues from Saw VI, he has not got a chunk missing. (00:09:00)
Answer: Dr. Gordon from the 1st movie, and Ryan and Brad from the trap in the beginning of this movie.
derrick g