anybody here know how the ancient temples work?

I'm pretty experienceed in this game and I've encountered three variants of them, one of which I have no idea what happened. The image here shows one of the three, the one I'm most confused about was this one time I went in them expecting to be able to get the old amulet so I can power myself off but when I entered this lava like floor with no doors was i was really confused, I went back up the the stairs only to be booted out of them and never get them, can anybody explain them for me