I read somewhere that Byng Hun Lee's character, Han, was partly motivated by a desire to grab the ever-growing Chinese audience (although he is Korean) and that trailers for the movie screened in that part of the world would more heavily emphasise his character.
I suspect this theory is true. Because in the movie itself, after our main heroes have vacated the scene, the camera stays with Han while he takes down a bunch of Russian police. The way the camera frames him in that scene is as a hero, despite the fact that he's working against the protagonists and trying to kill them at every opportunity. You're meant to like this guy.
Also, there's the fact that he is the flim's eye-candy (aside from Helen Mirren, of course.) Don't believe me?
He gets naked in the first five minutes of the movie. Anyway, if Hollywood's going to start pandering to an asian market, I can only see this as a good thing. I was sitting through the previews before the movie and it was just, white guy, white guy, white guy with a black offsider, white guy. Putting aside social justice and racial equality (not that we should,) it gets fucking boring.