Are you sure you want to delete this?
I have been through this problem as well, what I would do is to diffuse light the best I can and try to and try to backlight it a little bit just as Mike said. The result I imagine would be a very even overall light so you can't tell very well where the source light is and would be a dark mood as you say. Would that still count as moonlight though? The film still I got it from Haunting of Hill House, and I would light it maybe less prominent to what you see in the picture.
Please post pictures of your BTS when you film the scene, I'm curious of how it will turn out.