Linfel's group didn't leave the city through the gate like the last time. Usually, Linfel would have everyone run and battle all the way to the Crystal Caves. However, because the next Magic Control Test would take place in just one month, they might run out of time. That's because the Crystal Cave was over five thousand kilometers away.
They went to the public airship transportation and paid the Ventis Credits fee. No one would believe Level Three would spend their Ventis Credits on these things, but Linfel's group definitely did. They got even more Ventis Credits after returning from the previous dungeon. Right now, their total amount was 1147, after paying for their seats in the airship. They could have even more, but they spent quite a bit here in the city before leaving.