"Oh, yes, no, I certainly do not want the Ministry coming down on or to Hogwarts, not over this, no matter how much my civics says that as the government this sort of thing is what they're for or else why have them; it'd be like using a blasting spell to stun somebody.  Even as this is, in fact, some kind of crime, there's a war on, and there's only so much time in the day; I for one would prefer it be spent on...  More pressing matters than something where everyone survived just fine.  Much better that inquiry here be settled before justice is done by appropriate authorities."

She pauses.  Considers.

"...Let us hope that no-one has been foolish enough to attempt to breach Dumbledore's boundary from the other direction.  The consequences could be worse.  Especially for the children that they would affect."

Theatrical shudder. "Merlin forbid. I should like to hope Dolohov still has enough soulspark(*) left in him not to order an attack on the school even if the bloody Dark Lord says so, but you never know, with people who decided to work for the megalomaniac in the first place. Well, rest a tiny bit assured that if you should find your mystery assassin was acting on outside orders you can probably go straight to the Minister. At least three-quarters of the country will set aside their differences for five minutes to come down on whoever was that stupid like Salazar wielding the Sword." 

(*) a term generally used to mean the ~goal-orientedness of a wizard's soul, a quantity obviously difficult to empirically measure other than by counting how often they do things which further their goals rather than actions which do the opposite of that, but which some have hypothesized affects how likely you are to leave a ghost; idiomatically used in the same way people on Golarion use 'Wisdom' and mundane Englishfolk use 'common sense' and so on. 

She nods, firmly.  "Stratego-political concerns aside, this is a bit more than jinxes to the back in corridors.  I do not like the escalation.  Even if it wasn't likely aimed at me...  If others imitate even some of the methods I will need to know how to defend myself and my -" she doesn't say friends - "and any other people who might get caught up in schemes aimed at me."

"The result might be crude but the method is not at all easy or imitable. Still, it's a very reasonable concern." Thoughtful hum. "Well, now I've met you for reasons that were definitely not us conspiring and no reasonable person could claim we were introduced by someone who wanted to get you inducted unconscionably early into secret paramilitary organizations that shall remain nameless," she means the Order of the Phoenix, which definitely doesn't exist and she is even more definitely not in it, it would make battles really confusing! she just Polyjuices McGonagall in the field, you see, "so it doesn't count as Hogwarts interference if I invite you to volunteer as a research subject for my next paper," she means Legilimency tutoring, "though unfortunately since you don't have Hogsmeade privileges yet I suppose it will have to wait for summertime. I do not think I can scheme you out of that particular reasonable rule." 

"Oh, my favorite, walking into a room full of Slytherins saying things about schemes," says, dryly, the cheerful voice of a seventh-year Hufflepuff that Ophelia will of course recognize as Andromeda's boyfriend. (Or perhaps fiancé. It's a bit of an open secret they are planning to get married on graduation day, i.e. the minute they're legally allowed to. People with no taste have been cracking jokes about Ted's impending death for months; Ophelia has likely figured out the considerably less open secret that unlike Cedrella, Andromeda does not particularly want her boyfriend to fight Arcturus for her, and they're also planning to flee the country.)

"Hey!" 

He pats Nelya sympathetically on the shoulder and then scoots promptly out of the way when Pomfrey makes a disgruntled noise at him. "You count, you married in."

"Says the kettle to the pot." 

"Fair cop. What d'you need, 'Dromeda said something I vaguely understood to be about our arithmancy project but she was kind of too angry to talk?" This last is directed at Ophelia. 

There is a considering hum at the mention of secret paramilitary organizations that shall remain nameless.  She hadn't been quite sure about anyone but the mediwitch.  "I look forward to pushing the limits of our knowledge, then, come summertime.  I will of course gladly take book recommendations in the meantime."

And then, Ted.

"Your Arithmancy project, or perhaps more truly your Arithmancy partner, was sabotaged and used as a weapon of assassination against Professor Weasley, which I was lucky enough to survive and help the others here survive.

"There was ...a diagram, of some sort, I don't believe I am the best source of those details - that exploded when Professor Weasley touched it.  Nelya had been holding it at the time and someone had - messed with her head, prior, so that her own protection spell went utterly wrong.  It - the not-your-project-because-it-exploded - was dispelled with a Finite.

"I'm guessing you're here to make sure that it won't...re-explode?  Or anything.  Or to..."

"...Well, I doubt the assassin is going to be quite so stupid as to come here.  Andromeda would have sent herself.  Alas that they --"

"I'm sure this is just a formality, but please prove to someone's satisfaction that you are Ted Tonks?  Just to be...sure."

She knows what Polyjuice does, it's an entirely reasonable precaution!  Even if it's highly unlikely!

He processes this, brows furrowing further with each sentence. "Well thank you and congratulations on the heroism but if it wasn't my project, and also exploded..." 

Cedrella waves the diagram of the explosion at him, but doesn't hand it over yet.

"Oh! Yes, okay, I can probably tell you what about this is different from our actual project, yeah. What's that about proving something?" 

"Traditionally you'd be asked to demonstrate clear recollection of a private conversation, though personally-" 

"No, 'he failed his Potions OWL' doesn't tell us anything about whether someone else who wanted to impersonate him might have the relevant skillset." He's really so spoiled by being so good at murder that he doesn't have to pay attention to politics. 

"...As I was saying, though personally I'm disinclined to trust that sort of thing since I'm quite good at spoofing it. You'd want something else reasonably unique to yourself, which perhaps your professor or your acquantaince would recall, though having never met you - " 

Ted blinks a little incredulously at her for a moment and then turns his entire skin surface mermaid-scale blue. 

" - ah. Fair enough. Prince, that seem right to you?" 

"...Seems sufficient.  And really no-one would be both this brilliant and simultaneously that stupid.  Vis a vis not accounting for me, and then expecting you."

Snicker. "As a general rule you should not assume Death Eaters will not be even stupider than you could possibly imagine, but in this case yes, I agree." She hands over the notes. 

Ted squints at the pages, and then opens his mouth, and then reconsiders this plan and takes several steps through the adjoining classroom door into the duelling arena, and then shuts his eyes and reads off from memory a chunk of what the spell is supposed to look like, sending a spiral of floating blue numbers and arcane symbols dancing around his head. "Oh, for god's sake, hold still," he tells them irritably, and they corral themselves into a stack, almost apologetically, to be compared to the page. "That looks right, that looks right - wait how did it get to that from -" he prods one of the floating numbers with his wand, and flips its sign, and it throws off some green sparks, and then flips back. "Yeah, see, it should be self-balancing, they don't like it when you do that..." 

The whole vibe of his mental presence shifts, rotating out of words and concepts-shaped-like-nouns and into mostly shapes and concepts-shaped-like-verbs, as he visualizes the spell structure and tries to figure out where some logical connection has gone astray. 

This may take a minute. 

Cedrella tilts her head fascinatedly at him. "Maths-ravenclaws really are such a way, aren't they. I've never been able to do that myself but it's such fun to watch, no?" 

"Goodness, I shall have to learn how one does that at some point.  It's...It's beautiful, isn't it?  I think it is.  Even if my maths skill isn't to anywhere where I'd have the foggiest idea what any of this is.  Let alone the Arithmancy.  Yet.

"...I've no grand talent in the field as far as I know, even if I'm working ahead somewhat compared to where the other Muggleborn children 'should' be based on their schooling - but that's, mm.  As much the course of study's fault, as anything's.  I feel it doesn't...  It focuses more on rote learning and memorization of outcome than, oh, say, understanding why math works like that.

"...I wonder how all the weird maths constants behave when you're doing that.  Is pi, pi, or just however much of it you've memorized...?  I suppose I'll have to look it up."