Whoa, whoa, whoa.
Timeframe in this story is a bit before the events of the Mistress Spanks twice as they are now. So this is supposed to be just you playing Brionne here. When I said show up over here, I meant show up as a player, but playing Brionne, not playing Alexei trying to stop Cumhachd.
Here's the order of events:
Cumhachd had her note delivered by a page, meaning she was in the castle, already. Once she had ensured that the note was on its way, she found an out of the way spot, transformed into Twigberry, and came up here and took Apollodorus's book. She then secured that book, resumed her form as Cumhachd and returned to Mons Electi and acquired the Magic Theory text in the library. Then she paralyzed the Alexandria as she started complaining about taking the book. Cumhachd then secured that book, and shortly after that (few minutes later) Alexandria came into the council, told Alexei and the council about the Magic Theory text being stolen, and shortly thereafter, Cumhachd secured Loys, but that happened after Alexei is in the Library. Even if Alexei had gone to Apollodorus's library right away, it wouldn't have mattered, the dead would already have been done.
So, Alexei can arrive on scene, see Brione and Junior paralyzed, but it should happen in the other thread. Because here, is just about Cumhachd taking the book, and Alexei and/or everyone else doesn't find out about it until after it's gone.
No one seemed interested in character dialog with Cumhachd/Twigberry with one of their grogs, so we'll just call this story done, and it never lived up to it's potential.