I′m in this dungeon trying to bring home an Acrobat. I′m at a door right next to some water and I seriously don′t know how to get it open so I can walk into the room. I could interact with the door if only I could look up while standing in the water but as I can′t do that... well, I′m stumped.

Is Passwall the only option here?

Arena is a game where you have to find the hidden switch or level or lock or trap. It may not even be in the same room as the door you need to get through.