Visible crew/equipment: When Glenda electrocutes the security guard and his face bursts into flames, you can see where a flammable substance has been smeared on the prop head. It's sort-of whiteish, and the flames immediately ignite on it.
Visible crew/equipment: When Father Bryce is locking the students in their rooms near the beginning, when he locks Trevor's friend's door, there's a close-up of the door handle. If you look closely, you can see the reflection of the camera with a black covering draped over it.
Visible crew/equipment: When Lexy is scared in the classroom and stands up, there's a closeup of her eyes, and you can see a very clear reflection of a lighting bounce-card in her eyes.
Answer: Presumably she's referring to Jake, Devon, and her sister Caroline, since they're the ones who are most "in the know" about the problems Lexi is facing and maintaining her secrets.
TedStixon