The Trap Door

There's no obvious work or research purpose to this space. There doesn't seem to be a way out of here. I was expecting the tunnel to continue on the other side, but it doesn't. So maybe there's another way down to the shore. Or maybe I missed somewhere back there where the tunnel bridge is off. A trap door. It's circular, made of metal with holes punched through it, kind of irregular holes. It reminds me of when I used to collect insects as a kid and put them in jars and then punch air holes for them. The last place was books and experiments. But actually, I'm not sure how much we've got turned around so... Okay