Oh come on, petrified wood shaped like a heart?

That's gotta be the source of the roots in the building. And, of course, why the stabbed student won't touch any of the roots. Maybe try slicing off a piece of the root to use as your own charm?

I'm gonna say something that was in the back of my mind this entire time - What if the Rain Chasers aren't entirely... "student-run"?

The administration doesn't touch them. They were basically human sacrifices for the Eye. And now after their abandonment, they're back for more.

There has to be some kind of inside force keeping a group of people ready to be used as needed.

You should probably join the new Rain Chasers more inconspicuously than you might want to. Genuine ideas about how to disrupt the inhuman might not give the best impression of you, especially when you're directly in the spotlight administration-wise.