Knowing 8BT nowadays I can tell you that they'll get out of it cuz Garland mixed the acid badly, so it's a giant vat of healing potion. Either that or they'll remember that Red Mage can cast destructive spells (or that Black Mage can cast one of his non-level 9 destructive spells) to get them out of there.

When the smeg is BB gonna say anything?!? (Come to think of it, Thief ain't said much either, but he's said more than BB.)