Lighting a tunnel scene
 

I want to light an outside scene that takes place in a tunnel at night. I recently saw the Descent and notice that they don't use much in the way of light, so I was wondering how they got such a nice look without all the grain? When I light this tunnel scene, I don't want any unnatural looking lights, maybe just a flashlight...any ideas?

So, the questions that come to mind:

What are you shooting on? type of camera or type of film stock

Can you see out of the end of the tunnel?

Is there motivation for light in the tunnel? What are the characters using for light?

And just be aware that it sometimes takes a lot of light to make it look dark. I'm guessing that's what you're seeing in Descent.