[Ren certainly can't see her arm, but he did, at least, see the door, and it's hard to misdirect himself too much on what's essentially a straight shot, so he keeps walking forward at a slightly more brisk pace now that he knows he's not just going to walk straight into something. Probably.]

Right, right...it doesn't look like it's too much brighter down there, but maybe we'll be able to see something more when we get there. [Even if the lights are on the fritz here, it's possible that door might have other paths from it, and that some of them might have visible lights to use as a guide.]

I wonder how many people usually live on this ship, if there's this many rooms...