Sid's Amputation
Key moment in this sequence is the tilt and pan down from Sid as his curiosity drives him to look at where his amputated foot was. It was important we still see his real leg and see that is has been cut short, his foot removed, all in one shot, no edits. Of course, there was greenscreen and a hole in the bed, however the illusion is sold by seeing his real leg, the stump and see how it is raised as he tries to look at it.
The timelapse, music, and changing focus adds to the dreamy feel, almost as if the anaesthetic is at work on our consciousness.