Etsu, not exactly a shining example of adult maturity herself, interprets and understands Kazu's disappointed expressions. When you learn the super cool fireball lightning explosion technique, you want to bust it out every fight, any chance to show off in front of cute girl teammate, all out fights surrounded by entire villages in the Chuunin Exams arena. Kazu would be denied this. Kazu would probably use this technique more in private than in practice. Even grimmer, Kazu probably should favor leaving as few people alive that witness this technique as possible.
"Heyyyyyy, no pouting," the sensei tries to ease over, sticking her tongue out of her mouth, which is somehow oddly as thin as her lips. "Your'e basically getting invincibility as long as you're awake with this bad boy, you know?" She shakes his shoulder playfully, which doesn't match the rest of the conversation at all.
"Yeah so, uhh, training.... hmmmmm..... it's like........ you remember ol' Shakuna Uchiha?" Kazu, especially as an Uchiha, not that you need to be to know this local celebrity, would surely know who he was. Just in case it slips his mind, Etsu clarifies: "The one with the eww-gross giant hole in his cheek?" That ought to narrow it down. "Classic story. tries to learn fireball. blows up in his mouth. lives life with one less cheek all Two-Face style. sad. secretly funny, but sad. Anywho: most jutsu can be learned with low risk-- it's whatever. But you're literally altering space and time and physics and I-don't-know-probably-more-Steven-Hawking-type-words. There's a lot of things that could go wrong. You could...."
Her eyes shift to the side and go to a dark place for a while....
Etsu tapped the smooth, circular stone from the river and tosses it across. On her command, that tap formed the simply intricate design of the Flying Thunder God seal.
"This is it.... your whole body, Etsu.... every bit of it.... every molecule," she mouthed to herself, stepping in place nervously. A large sigh seemed to drown out the area; the river became stagnant, the wind was still, and no bird or fly or leaf dared to move. The world waited for Etsu to defy it in that moment,
more hanging on that millisecond than her years of experimenting and researching and planning. Becoming Jounin, for her, gave her permission to finally test it; she was sure she had it all right. Now all that's left to do is.... become nothing.
The blonde's image escaped reality, erased from sight just as it appears at the rock thrown across the river. She caught her balance, despite not being off balance at all,
and glances around. The river is on her left when she looks left, and it is on the right when she looks right. "I.... I'm across the river. It worked. IT WORKED! It-- AUGGHGHGH!" Her slim body thudded loudly and cruelly on the rocky shore, overtaken by the sudden realization of sharp, intense, overtaking pain. The struggle to remain conscious was somehow both aided and afflicted by the incredible physical toll she suffered in her side. Howling in pain, she wrestled with her sensations on the ground, clutching her side. The water near where Etsu used to be turned a shade of pink before diffusing back to normal, the soft, slimy rolling of a small section of the girl's entrails unheard as the current dragged it slowly over the bordering stones. Etsu spits blood.
Subconsciously, her hand reaches for her side. "There could be complications."