Rhiow spoke the spell rapidly - not so rapidly that she would stumble over the words, but rapidly enough that Zuko likely wouldn't get another chance to breathe fire on her. The two of them disappeared with a whump.

Seconds after dropping Zuko off in containment, there was another bang and Rhiow re-appeared, yet another spell circle beginning to materialize around her. This would be the last one for a while - she was panting a bit with exertion. "Ready to go? I have it set for observation."