This is a foreign language film (possibly Korean). I can remember a few scenes from this film.
The first scene I remember is where someone gets killed by their reflection while in a public bathroom. One image I remember clearly is a close up shot of blood slowly spreading to fill the grout lines between white floor tiles.
I think there was another scene in an elevator, again involving something to do with the mirrored wall.
I think the building was a newly constructed commercial tower block with office and retail areas.
I saw this approximately 6-10 years ago.