Earlier today, I defeated a particularly hard boss and felt pretty good [optional boss in abyss.] Afterwards I went back towards the beginning of the game and searched for stuff I hadn't gotten, and obtained the.. err.. well I've forgotten the name of the item. It's the warrior costume, presumably the first one you get.
Anyway, when I left this small place, I found that the rock which I had to move to enter the place had either a) moved back into its position, b) I accidentally moved it back into its position with bind. I don't recall which, but unless I'm a complete moron, at this point I couldn't get out and had to close the game.
It's possible I'm a complete moron, it's happened plenty of times before, eh? Just thought I'd let my ramblings be heard before I went back in to kill that abyss boss.