Getting behind the red building next to the arena.

[WalceDony]

If you try to walk behind the red building next to the arena (No idea what it's actually called...) you are not able to; however if you use dodging strike to boost yourself behind it, you can walk behind the building.
You are able to easily walk back out again, but since you can't get there without using a skill, I don't think we should be able to get there at all.