In Jigsaws lair, where he was caught, you can see items around the room from the house in which the 8 victims were being held. You can see the oar Amanda picks up from the basement and the X marks the spot photograph. These are clues to show that the camera footage is recorded. This is confirmed on the DVD commentary.
In the room with the razor blade box, if you look at the top of the frame, you can see a lock with a key in it. If the actress walked a few feet further, she could've unlocked the box and gotten the syringe. Obviously this would've defeated the purpose of her dying, but interesting to point out. Confirmed in DVD special features.