Visible crew/equipment: When the police cars arrive after Strahm's cube trap, there is a very quick shot of the black police car passing before the camera. When it does, a white screen and black stage light are reflected on its surface. This is just before it shows the SWAT going in. (00:10:45)
Visible crew/equipment: When Jill Tuck is talking to Agent Erikson in his office, there is a shot with a boom arm's shadow visible across a picture and bit of wall, behind Agent Erikson. (01:03:40)
Visible crew/equipment: In the crushing room at the end of the film, Strahm is trying to open the box where Hoffman is. As it's descending into the ground, on the side of the box you can see the feet of a crew member with white sneakers moving around. It is not Strahm's feet: he's wearing black boots. No slow-mo is required.
Visible crew/equipment: When Strahm goes to get his gun in the crushing room at the end of the film, a boom mic is reflected on his jacket.
Chosen answer: Assuming the woman in the bathtub was able to be moved safely the amount of blood gained from her, while still being helpful, would probably not be enough to save the final two survivors from self harm. Without the heart pumping blood you would only get the blood that was in her arm at the moment. You would have to lift her or raise her so gravity would get other blood moving to get enough. Which the final two possibly could have done, but stress of the situation clouded their judgement.