Hi guys, in pokemon emerald, I was stucked at this stage where I am suppose to being able to use "Flash " to search for HM07, also known as "waterfall" but threre is only a dead end whereby the place where I encounter wallace and talk to him, also I can't go access to the gym as its still being blocked by Aqua boss. I can't fight both legendary pokemon. What am I suppose to do next? Please assist asap!