Help with Final Fantasy IV advance?

in the sealed cavern you must go all the way. to the end. have you? did you fight the demon wall? if you did all you need to do is go out of the cavern. when your leaving kain will take the crystal and run off. end of the sealed cavern part. for more help go to a href="http://www.gamefaqs.com/portable/gbadvance/file/929937/40844" rel="nofollow"http://www.gamefaqs.com/portable/gbadvan…/a