He's supposed to be a supervillain-level mastermind, a real life Lex Luthor. And he's been held captive by this organization for 15 years. So he'd have had plenty of time to learn all about them.
In the end, however, all he really needed to do is make sure the confrontation between Dunn and the Horde streamed out to his mother. He didn't need to know the clover organization even existed, although I'm betting he did know.
I thought Shyamalan always had a trilogy in mind, where "Split" would be the second film. Specifically, I recall reading that Dunn's story and the Horde's story were meant to be interwoven, but he eliminated the "Split" portions from "Unbreakable."
So this may just be me fanwanking here, but I think the clover conspiracy may have arranged Elijah Price's incarceration in one of their own facilities from the start. Then they sat back and kept an eye on Dunn. That's why they were so well-prepared to "arrest" both Dunn and Crumb at the brick warehouse.
It's also why several facility employees are shown attending the conspiracy's debriefing session. Shyamalan wants us to know that the entire facility was under clover control, all along.
It also makes Elijah's posthumous triumph more credible: he's had 15 years to discover, study and ultimately defeat the clover conspiracy, turning this "limited edition" into an "origin story."
I didn't notice that it was a clover controlled facility.
and i didn't think about the fact that it was essentially clover who arrested the other two.
I like that it was a clover controlled facility. it helps to alleviate the possible criticism that it's unbelievable that someone like crumb would be held at such a seemingly understaffed facility.
i'll tell you something about how much I liked this movie.
you know that stupid bullshit in american beauty where the guy is all like "I cried because the plastic bag was so beautiful"?
i cried during the end credits of this film because it is the beautiful plastic bag. (I'm a 38 year old guy who is not known for being emotional)
it's the only time that has ever happened to me.