If you fury your characters, you will usually hit your limit break with one hit of his spell ("Everyone's Grudge" I think it's called.) This is good for raising your limit level if you haven't gotten the lvl. */2's yet.
If you don't wanna run into emerald, just go to it above water then drop down. Though, after awhile emerald just stays in the same spot (near the red sub.) Anyone know what the condition is for him to do that?