You exit the secret lab and return to the main room. It seems bigger than when you were in here before, but, somehow smaller. I mean, it feels larger simply because you were in a very small set of rooms for several minutes, so you felt accustomed to their size, so this massive, open space seems quite large. But it seems small because you as a person feel larger, in that you feel more understanding of whatever this whole system is.
What you understand of the whole story is that around 37 years ago, a little owl girl was growing up in a very large, and technically advanced laboratory, all alone, with only a very long trail which led to the rest of her kind, that being monsters. As she was growing up, she had free reign over a massive selection of machinery including a session terminal, an ectobiology machine, and a transportalizer. One day, she found that she could travel from her lab to the lab of a very interesting man. The man invited her to join his company, and then she was put onto a very important project which involved cloning children. After several months, it was finally time to get it correct, but then it failed, and so the project was cancelled. Devastated, the owl decided to continue without her boss's permission, and in the process, creating a bunch of clones of you, all seeming to be malformed, and from records, being able to remember future events. After some time, the owl made a clone of herself, but then found out something dire, in which she needed to give away her clone and kill herself. Then, that clone grew up as your sis and then when the barrier broke, the two of you moved into your family's lot, which just so happened to have the same lab that the original owl was growing up. In the end, your sis probably new all this info as soon as she started going into the mausoleum.
In fact, you suspect that the whole mausoleum glowed green before your sis discovered it, and then she put a magic spell on it that forced it to be pitch black. You remember seeing something down there and then never again. You also remember helping out your sis with this lab. You remember having to fly to the top of the house to look at a screen if it was on while she was playing with something in the lab. That must be what all the large antennae are for.