Got the two keys, opened the two doors, got the orb, but unfortunately I fell through the trap door just after the doors and before the teleporter. And that trap door never closed again. I might've done something wrong :(
that trapdoor reopening was actually a bug, the default behavior for trapdoors is to automatically reopen after a delay. there is a setting to make that happen only on demand, but that particular property didn't get imported from my layout tool.
