That...that was it. Zuko could only be so nice for so long. And this pathetic excuse for a bender wasn't even trying to be civil with him. He got that she hated him, he really did, but this wasn't about that. It was about her learning to defend herself against things in this world that were immune to waterbending. Why could she see that!?
Stepping towards her, Zuko raised a hand and ignited a flame across his fingers, but her brought it down town in a flash of fire, extinguishing it as he balled a fist in fury.
"WHAT THE HELL IS YOUR PROBLEM!?" He finally shouted at her, the temper he inherited from both Sozin and Ozai shining brightly. "I am trying to fucking help you, but you are refusing my attempts and being rude in response to my kindness! You don't like me, I get that. But this is not about ME!"
Zuko took another step forward, bringing his fist up as he sneered at her. "There are creatures here that can't be harmed by bending, Katara. And if you're going to not get eaten by them, you need to know how to kill them. And using these weapons will do that. But, if you would rather some demon make you it's next dinner, that FINE WITH ME!"
He stormed away from her then, heading back up the stairs while cursing noticeably under his breath. He didn't say upstairs long, for he soon returned with a handkerchief in hand. He practically threw it at her, crossing his arms as he glared golden daggers at her.
"Hold it to your nose and tilt your head back to stop the bleeding."