Very nice. Lighting and texturing are lovely. The ceilings, if they're rock, might look better either as simple patch meshes or trisouped to make them seem a bit more natural. If that's what you were going for, anyway. The floor, as you said, could use a little detail work. Not overkill, mind you, but something, as it does look a bit flat currently. Perhaps some trim along the wall. I personally wouldn't go for something flashy like intricate floor designs, etc. as from my POV that's not really what this hallway is about.
I personally think that one of the greatest misconceptions about level design is that everything HAS to be insanely detailed and intricate. Not to sound insulting, but the shapes I'm seeing there are pretty simple, and yet it all works together fantastically. The texturing and the lighting only helps this. Simplicity in design can be even more aesthetically pleasing than the most complex and intricate architecture that you can accomplish. This exemplifies that.
If I can bother you for a second, is that one of the standard texture sets that comes with JA? If not, then where'd you find it? I may have a use for those...
I believe I speak for everyone when I say: "MORE PICS!"
------------------