It may be that simultaneous worlds co-exists like many TV signals are on the air simultaneously, but we see only the one TV-signal we are "tuned into"- *ordinarily*- but just as certain conditions (like intermodulation) can cause one TV signals to bleed into another, so can certain things warp the space-time continuum and have one dimension leak into another.
(PS- If anyone wants to talk about TV intermodulation- I once wrote a article on it)
