UHHH. I have committed dubious! Sooo people reported that you could jump over the dev girl that's supposed to block you from most of the water area. Taking that knowledge, I explored there as far as I could (Yes, I know the dangers. Oh, and if you don't know the dangers, DON'T DO THIS. It could corrupt your saves later when the areas are actually released). But then I got curious as to where else I might get. I GOT HERE. So the ladder just past the dev girl blocking the slime area functions. You just have to jump juuust right to not overshoot. You should probably disable that for now, or link the warp to a temporary event that teleports you back and text boxes something like "nice try but don't."