You never know. Although I'd be surprised if they don't have something equivalent. I can't possibly be the only one with the idea. Since the vampires live in their eternal darkness there's no way of knowing. Istredd knows that he is ultimately a very paranoid person. They both are. It wouldn't be difficult for him to simply explain how he does it if there ever was a need.

I'd hate to live in eternal darkness. There would never be enough light to read comfortably. Yes he knows they have bright lights but nothing is better than actual sunlight. And yes Istredd is that much of a nerd that his first argument against eternal night would be to read books better.

Istredd knows Lucifer is very aware of him and he is glad he's not making it obvious. He's frustrated enough at his inability to logic away an illogical feeling of dread. It's putting him on edge more than the fear, his anger at himself. He is keeping it from bubbling over to Lucifer as best as possible.

I don't blame him. They've clearly had no power for a very long. What hope do they have of excelling at this point? The relationship between Nott and the crown only gets worse. But they don't have the money or the ability to become thriving in this situation. It's a no-win situation. Thorne isn't going to be the answer. Eternal night might be the only one.