Why had i never thought of it before?

It's so simple and I feel foolish for have never doing so. Especially with the second book.
Sibling rivalry.
I briefly allude to it within The Dematri'aan Chronicles and somewhat in The Princess Odyssey with Layanna taunting Elloria for her obsession with humans. But I've never shown them as sisters so to speak.
I've always based their relationship on the one I have with my own sisters, in that we're supportive of each other, playful and will tell each other straight, but the rivalry dynamic between us does occur from time to time. And it's always one on one with the other sister acting as a mediator that stops the "fighting".
What you'll read next is a rough draft of one of these spats between the Fae sisters, and whilst the situation is unique to me, the overall tone is something that I have experienced, and any feedback would be welcomed.

Key: E = Elloria. K = Keela. L = Layanna

* The sisters hear something rustling from beyond the bushes, a bear springs forth.
E. "RUN!"
*The sisters run, L looks back, trips. She turns over and backs away on her rear, calling for help (movie cliché)
* E comes out of nowhere with a dagger in hand, jumps on the bears back and stabs it repeatedly in the neck until it dies.
* L gets up.
E. "I told you to run! Why did you look back?"
L. "Because..."
E. "No, not because. You sacrificed footing for a glance at your assailant. You lost focus!"
L. "But..."
E. "And then you stayed on the ground, cowering".
L. "Yes, but"
E. "Next time I tell you to run, you run! No looking back, just move as fast and as far as your legs can carry you."
* L pushes E
L. "How dare you talk to me like that! You may be my Queen, but you're still my baby sister"
* E pushes L
E. "I'm sorry for wanting to try and keep you alive. But lest you forget, I've been in this situation before! You think a damn bear is bad? Try running from a black, shapeless... Thing, in the dark with little to no light and terrified because it's hounded you for over a week and nothing you do to it seems to even have the slightest effect!"
* E pushes L again
E. "You want to stay alive, you do as I say! So if I say run, you run. Do you understand?"
* L slaps E
L. "Don't you ever talk down to me sister!"
E. "Do that again if you dare"
* L slaps E again.
* E raises her hand, ready to strike L, K grabs E's hand and stops her.
K "Will you two knock it off?"
E. "She started it!"
L. "Did not"
E. "Did so"
K. "I don't care who started it! I'm not going to walk through a strange forest on the other side of the world with you two fighting!"
E. "Whatever"
* E storms off, angry.
L. "Oh that's very mature and majestic that! The mighty warrior Queen of the Fae, sulking"
K. "And you can shut up as well! I don't care if you're the eldest, or if she's the damn Queen, I'll knock both of your arses to the ground if you carry on!"
L. "I'd like to see you try"
K. "Don't tempt me... Now move!"
* L sets off, gritting her teeth and mumbling incoherently. K sighs and follows.