Elevator Scene - No Camera Reflection
While there's been a bit of bashing of this movie for being slow and boring, the whole film is filled with understated bits of genius. The Guggenheim scene is quite possibly one of the best action set-pieces of *beep* just starts happening out of no-where" moments. There are a lot of things that happen in the background that are pretty cool that you just don't notice - when you just need to stop and take a second look.
One of these is in the elevator when Clive and Naomi are on their way up to see the Italian arms manufacturer. The camera is pointed to them as they stand with their backs to a mirrored wall. You can see the elevator doors opposite them, which then open to show the guy standing outside.
This scene is pretty cool because - normally, you would see the camera in the reflection - but it's like the camera isn't even there! It's invisible! I'm sure there's some post-production trickery here, but you don't even notice it.
It's a general theme that runs through the movie - things happening that you don't notice.
Check it out.