Homura groans and stares over at the other girl, well at least she knows for a fact now... Here comes the hard part, figuring out what to actually say about it. She guesses that there's only thing to do now however...
H: "It's a long story, but in short I've been where you are now Sonomi. Now I've already told you some about being a magical girl, but here's the deal. You could stop, I know a way to do that... Something tells me you aren't gonna though, right?"
She'd pause for a moment, cracking her knuckles absently while watching the shop become even more empty bar the utter weirdos present. Given that, she goes on a bit further with a worried smile.
H: "There's only one way to keep it up, fight and kill witches... I can't exactly fight all your battles for you, nobody can. But I can try and help you get better at fighting them, and much as I hate to admit it I'll get involved myself too."
What's the most important thing to remember though... Above all else. Oh, she knows.
H: "Keep in mind when it comes to witches, don't ever assume you know how to deal with them, don't get careless. I've seen a girl lose her damn head for that mistake, literally... Don't mess around, don't drag people who can't handle themselves into a barrier, and don't waste your magic."
All of that is good well and practical, but there is another matter at hand... She smiles lightly while her voice softens.
H: "And for gods sake, try to remember that you matter too dammit. I get that you want to help people, but that doesn't mean you should be willing to toss your life aside Sonomi."
She'd just grin a bit while waiting for a reply to that last remark, hand held out towards the other girl.
As for Madoka, she sighs a bit and shakes her head while staring at the boy.
M: "I... Try to be careful okay. And do me a favor, promise you aren't gonna turn into a constantly snarking fight loving weapon salesmen at some point. I know how oddly specific that sounds, and there's a story there..."
She just groans while even pondering the thought, of her brother acting like a certain other Tatsuya she only vaguely knew of. Truly, terrifying. Sends a shiver down her spine really.
M: "Now there's a bad thing to ponder..."