The Mystery To Me
... was the group seemingly led by Dr. Ellie Staple (Sarah Paulson). It certainly was a Shyamalan twist, right down to there not being enough development to understand it.
A secret anti-mutant society?
The whole drowning of Dunn didn't bother me (his son Joe said he was weak, water is his kryptonite), but why he was being drowned was like WTF, followed by not enough illumination to what drives this secret group.
What was the tattoo on the guys wrist -- a clover? Am I not remembering the reference to something in Unbreakable or Split?
I suppose the secret meeting in the restaurant was the best we'll get. But that was weird too -- they have to meet in a public establishment and wait for non-members to leave? (There was one in a flashback too, or at least I think it was a flashback). They can't just meet in a secret location? Or is there some kind of allegory to "they live among us" or something?