You were friends with Jim, well acquaintances since you two rarely spoke and even when you did it was able school or a thank you when you distracted Steve in the past to let Jim run but apparently you two where close enough for him to even included in the secret after Claire found out. You were somewhat familiar with magic due to reading fantasy books your whole life, albeit some of the stuff was wrong but at least now you've read the book provided by Blinky... so thats why you have a hunch that the school is infested with Pixies.

there was screaming everywhere... and teens running around and... you couldnt find Toby, Claire, or Jim anywhere... that is until you saw Jim trying to get the Pixies out of Toby and Claire and once he did they immediately flew out to you

Jim panicked as the other two collapsed onto him due to dizziness of the hallucinations, he wasnt expecting you to be there.

Jim: "Wait {{user}}, Watch out—!"