This one was easy to figure out, there is a scene like this that totally puzzles me, it's from Fallen Angels, Wong Kar Wai, a couple are sitting at a bar, they are in slow-mo, and the background is accelerated... It looks like it's done in camera, but the only way to do this would be to have the talents act very slow... And that's not what they did, you can see it when they are blinking, they are in actual camera slow-mo, maybe 90fps, and the background is maybe 12fps... It's really weird... If anyone knows what sequence I am refering to, please post a link to it...I tried finding it on youtube but could not..
I don't know the scene but could it be a com posite or a projected background?