I did notice about the creeping darkness and did think that had to do with the fact that while I don't think we have evidence that Riley has done evil, he is definitely deciding to put himself into a position where he might. We don't get to judge because the situation hasn't come up. He seems to be thinking that he'll kill someone if Twilight asks him to as a test, but we can't judge people based on what they might do. For all we know, he'd have broken down and refused rather than shoot someone.

The pitch black *is* interesting. My read keys off the first bubbles in the dark "You really want to talk about this now" "You have something better to talk about in the total darkness". They go on to talk about their faith in each other and all that. There they are going into the possibilty of death and loss or the dreaded choice about shooting an innocent. It's an act of faith to talk about the future of their relationship. Faith is walking with surety through the pitch black (or unknown). I find it interesting that it immediately follows Angel on a church following what he thinks he knows (knowledge = light) into the dark, rather than trusting in the unknown (dark) in the hopes that it will bring him to the light.