"Okay~" He's a little less panicky now, but.. vague empathy comes with his race, he might be getting more confident because Mr Fire is confident. Zuko may notice its a little easier to run with this plant by his side - because, well, Asteffiel breathes out what humans need! He is a plant.

Asteffiel follows along right behind Zuko, dropping one more circle of magic. This one doesn't seem to do anything, just shimmers faintly on the ground like some sort of trap.

Trap is probably an accurate way to describe these kind of spells, because any of the monsters that come after them abruptly give shrieks of terror and fly in the other direction. He did say he could make them run away-