In a scene at the 15 minute mark in Billy Elliot where Debbie and Billy are saying goodbye, Debbie vanishes behind a passing vehicle.
I've seen this technique applied in movies where the whole atmosphere is supposed to be surreal or we're supposed to question a character's psyche, but I don't get that sense from this otherwise quite grim and realistic movie.
Any ideas?
Edit: I'm not sure it's related, but for what it's worth -- later in the movie we see a tired Billy imagine his recently deceased mother in the kitchen, then when he and the camera look back she's similarly vanished. That instance is a bit more logical/traditional.