I've got an idea for a little Easter Egg scare to tag on at the end of the trailer. Assume that you'd be wearing headphones for this....
The scene shows Yu on the phone looking at himself in the mirror. You'd hear the phone ringing coming from the right headphone and you'd hear it pick up. Then either you'd hear something talk to you and then hear it instantly 'behind' you (yay for binaural post processing) or should you just hear something straight behind you?
On both accounts of hearing the thing behind you, you'd see something appear behind Yu in the mirror.
Question now... which scene should this take place in? I've thought up of a train window (different train from the beginning), bus stop, bathroom, derelict hallway or a a conceptual reflection which doesn't give any hint of where he Yu actually is (but I'd need to draw some slightly more complex perspectives).
Ps some more inspiration: