Zuko had managed to jerk off to the side away from the flying object just seconds before it was embedded in the wall. "What is your problem?!" he shouted, completely ignoring what Robin had had to say.

A controlled thin stream of fire came to life at a single thought then, launched at the intruder, coiling forward through the air. Fine. If this guy wanted a fight then that's what they were going to get, death threats be damned (although Zuko had yet to actually hear one).