It wasn't his first reflex but Arthur decided to justify his needs. "Not that I'm willing to disappear so soon but my schedule is tighter than it appears. I have to get back with the colorful nobleman I have arrived with as soon as possible."
He wanted to get out of the House of Mages, going back to the palace was not an obligation. His other option was to wander around Tash, he wished to visit Lancelot's grave one more time and talk to it. Externalise his grief. But he couldn't do everything at once.
The messenger he had sent to Rainlet could arrive there anytime soon. A royal missive rarely happened and its importance could further hasten its bearer. Arthur hoped the omnimancer flying its way to the neighboring kingdom would do his best to shorten the deadline he had been given.