If that shit was happening in quest and we were in Chicago at the time I'd be advocating for people to move fast too. We don't know whats down the grapevine acting with haste makes sense.
Though if it'll take less than a minute and we should get essence regen I'm willing to just so we know more of her plans.
The problem with magic is that blundering in without knowing what is going on can make shit worse.
Or worse, might actually be part of your enemy's plan.
Even if unweaving works like that in WoD or ExWoD, which I doubt from looking at the rules for efforts more active than personal resistance, it shouldn't do so here. The DF never shows this sort of thing or implies it's possible.The best it has is warding and esoteric cases where someone gets magic resistance.
Nobody heard about the ritual in changes and went "let's get the senior council to set up a counter ritual". Odin, who taught Merlin magic and personally showed up for the fight at the end, didn't even mention the idea or appear to prepare anything in that direction with his cabal of high power mages.
When it went off precisely zero vampires anywhere on the planet or reachable areas of the nevernever survived, regardless of personal ability or patron's protection. This including all the people who actually put it together and knew exactly where its weak points would be.
That was a very powerful ritual, but it was also basically the red king killing mortals in a place of power he had for centuries to build up strength behind a punch. It wasn't revolutionarily clever or anything.
If "I have twenty occult dice and a relevant specialization" was enough to play counter magic games at this level then we'd see it used outside of fixed fortifications and direct interrupts of the force shield vs fire blast variety.
I'm not saying they're impossible to break, or that instantaneous defense shouldn't be possible, just casually undoing things like this with mortal magical traditions and no prep.
The difference is between a master sorcerer snuffing a ritual in line at Starbucks and the same person surviving until they can get to their fortified leyline nexus or what have you to fire back.
Unweaving undoes a standing magical effect.
Like unpicking a ward, or a curse, or a magical trap. Thats all Unweaving.
You roll Intelligence + Occult at DC8, extended rolls.
Something like the Chitchen Itza blood ritual was an instant effect, and you counter instant effects with Counterspell.
You would have gotten a single (reflexive)roll of Wits + Occult at DC8.
No Extended Rolls. Essentially the same thing that night people use to represent magic resistance.
Dresden did something like this in Blood Rites, when he parried/countered an incoming entropy spell, then used it to kill a Blampire.
===
Now a ritual like Chitchen Itza stacked up tens, or hundreds of successes. It was a group ritual, with many sorcerers involved.
There were hundreds of human sacrifices to prime it, and it was powered by a leyline nexus.
A bona fide legendary ritual according to Odin.
Your Celestial Exalt's counterspell pool of 20 dice will weaken it, but it wont actually make any material difference if you get hit with 190 successes worth of damage as opposed to 200 successes.
For something like that, you need either antishaping or a PD.