I've witnessed what Corey was talking about with David on a specific episode, can't remember which one.
The thing is, it happened 1 month before I actually watched the episode, so I had no knowledge of this before.
In my dream, I was taken to some sort of classroom by a very bright light. Was asked to sit down and study and reherse words of a language i've never seen or spoken before.
In this epsiode, Corey specifically said, that they were contacting people in their dreams and taking them to classrooms.
So yeah, I choose to believe them!