No chance of getting back to the surface at this point in time. Just gotta move forward, ya' know? Use the circular elevator platform to leave the Gear dock. You'll find Shevat's "overworld" screen. First keep checking around the SW section of the outer ring path until you get a DAWN ROCK, then head toward the red marker labeled "Aphel Aura", the ol' capital. Seriously though, where else could you MOVE a capital on this flying fortress?