Target.

Valerian woke up in the morning covered with cold sweat. He did not know why he dreamt of Rectus like this. He saw that the man was being held captive, in a cave. He also saw the cave to be hidden within a forest. He was not sure where this place was, so out of humanity, Valerian penned a letter to Azula so that the princess could check up on his situation. 

The boy did not even finish his meal and ran out to the posting tower of the academy. This was the place where all the administrative work of the academy was taken care of. It was a small castle outside the education block. 

Valerian passed on his letter to a staff member and asked him to send it through with the fastest postal service that was available. The students were allowed to communicate with the world outside free of charge.