I put the apparent light source in the mausoleum's secret room and why no one ever seems in danger of suffocating there in the same category as who the hell lights the seemingly ever present lit candles that will show up in the mausoleum's secret room in future eps, as well as the candles in the secret passages of Collinwood. It's all something that's never explained and something one just goes with the flow with and accepts. Kind of like watching Lost, a show where I also just went with flow and never expected everything to be explained. After all, when it comes to the supernatural, some things just aren't meant to be explained.
We do know that, but we try to make sense of it anyway. After all, no show can take an unlimited number of incongruities, and we try to limit them as much as we can, for the sake of protecting our suspension of disbelief.
As for Lost, I always thought that they set it up as a show where the explanations were coming, and mattered, so they (the show)couldn't really survive a lot of nonsense (and perhaps didn't). But maybe others watched it differently.