At the end of the path you'll go outside and face Bahamut. Like Leviathan and Odin, Bahamut tends to spam his all-party attack, Mega Flare. It is extremely powerful, but unlike Tidal Wave and Zantetsuken, it is subject to Reflect. You could have an Evoker summon Odin looking for Protective Light, or use the Reflect Spell and Shining Curtains. Regardless, each Reflect only works once, so don't count on an easy fight. Keep in mind that Bahamut resists all Elements, so Bio is your best Black Magic Spell for offense.
You'll have to walk back to the entrance, since Teleport will simply take you back to the inner exit.
You'll have to walk back to the entrance, since Teleport will simply take you back to the inner exit.