In creepy crypt, we can bypass the last fence even if we don't have key item which will be able to open the fence. Once pass through that fence to outside of cave, we never back into the cave and there is no choice but to give up this stage.

This bug is easily reproduced under any conditions, so my suggestion is system doesn't show dialog until player get the key item.

Please find attached screen shots for your reference(sorry for some Japanese words in this screen shots, I'm playing Japanese version)