Knowing things were going to shit, and flying the broomstick there, were two different things. Isaac would have been better off keeping his mouth shut and taking whatever Killian doled out. His nature was to argue with a Gryffindor, but acting out of pure self-interest was also his default. Isaac should have stayed quiet, but he didn't. Instead, he threw out some half-cocked insult, trying to bring the other wizard down to his level, and failed spectacularly. Isaac had been spending too much time around Magnolia lately, clearly.
Sucking a breath in through his teeth as Killian fired back, the Slytherin tried to shrug it off. Like the burden of figuring out the meaning behind Isaac's words was Killian's responsibility. "Hate-speech? The fuck?" Isaac's relaxed demeanor changed with the accusation. Bullying the first years was his right, a time-honored tradition of being both Slytherin and Upper Classman; he'd take that write up like a badge of honor, but the other thing was far less attractive.
Reaching for the notes floating slowly away from them, Isaac tried to intercept the one with Hate-Speech written on it, only to be zapped by the magic that carried them instead. Cursing under his breath as he shook out his hand, fingers still tingling, he turned his attention back to Killian. "Because I brought up Harry Potter? That is bullshit, and you know it, Buckley."
Isaac would serve the detention; once written, there was no getting out of it, but he wasn't backing down either. Maybe stubbornness was rubbing off on him, or perhaps he didn't want to be painted as a supremacist by a Prefect who knew nothing about him, but either way, Isaac wasn't going to be quiet now. "Are you saying I am not allowed my opinions or that your badge gives you the right to police them?"