I actually thought that that was going to be the case the first time I played the game and I felt disappointed by the actual result. I'd not played FFVI by that time, but it just seemed like a really cool bit of the game with all of your party members fighting together. At the same time I was relieved that I wouldn't have to fight a boss with just Eiko and Garnet. Though if it were an undead monster that would've been doable, I guess.