I watched this movie in June of 2009 on TV. It might have been a movie or a TV show but I’m not sure. It wasn’t that old and I think it was in English.

I remember a particular scene where this couple was running away from a murderer and they were both on a bridge. There was a wall that blocked the bridge halfway and the couple was trapped but the guy stalled the murderer, letting the woman get away. The murderer then kills the man and throws him off the bridge and I clearly remember it showing the body floating on the river. The setting seemed like it was in a dome and there were lots of trees and underground sewers.