Can you pose the character looking down off the bridge? Between her legs, as she is slightly tipping would give that little edge to her falling and add to the feeling of height. Also add some kind of light on the wall directly behind the bridge to add more depth and a bit of contrast/interest. And maybe another light source reflecting off the surfaces down in the bottom left corner? And possibly a downward spot light from the top of the pole on the bridge, just behind the character?
Maybe that's too many suggestions?