The first time I saw the BDM, in the scene at the end where Zoe tells Mal that the place they are is a good hold-point, Kaylee said that she could rig the blast doors not to open after they'd closed, and Mal suggests that doing that and then hiding was a better idea (Zoe, of course, disagrees). This is also in the novelisation. When I saw the BDM the second time, these couple of lines weren't in there. Then, when I saw it for the third time yesterday, it was in there again.
What's going on? How many people saw the film and saw/didn't see these lines?