Awesome tips Frag, I'll experiment with those. Like I said, the map was still WIP, and that includes lighting, I was naturally going to spice it up more afterwards, but I'm always open to suggestions.
One problem I've encountered though, is the fog under the room... it's very tricky. I had to extend the pit to be deeper than the room's diagonal and extend the fog accordingly, because otherwise the player would see fog in the corner of the room if he stood in the opposite one. I'm looking for a way for the fog to point downwards - or make the secondary one transparent, I tried directing the fog downwards and setting the secondary colour to white, then black, but nothing worked.