I have spent far too much time on this sequence. It's only a few seconds long, but I know if I can get the look and feel right, it will pave the way for other sequences of the film. I tried at first, just using oil pastel, but it wasn't frantic enough, so I have gone back over the frames with watercolour splashed all over the place.
I have also decided to use a couple of frames which are really photographic. Not many, just a few mixed in with the animation, to see if I can get a really jarring feel, whilst still hinting at a sense of reality. Fingers firmly crossed.