Cyclops outlines the recent events to him: i.e. that the Hellfire Club has gone after them. Warren, who is a member of the club, assures that them he is not the leak. Rather uncommonly for comics they raise the possibility that Frost's Hellfire Club might not be the same as the publicly acknowledged one that they are about to go after, but decide to investigate anyway. They wrangle invites to an event at the club through Warren.
This proves to be an enormous mistake as it provides the perfect opportunity for Wyngarde to transform Jean into the Black Queen, and attack the X-Men. Given her documented instability (and having finally admitted to Scott about the timeslips), it seems silly to place her in danger of further mental control. Although she's able to eventually able to break the conditioning, with help from the X-Men (particularly Wolverine, who the Hellfire Club had inadvisably left for dead), she has now become corrupted into a darker, and quite angry, Phoenix.
We discover that Sebastian Shaw is a mutant too, with motion-absorption powers. There's a chap named Donald Pierce, who is a cyborg. And a Harry Leland, in the Inner Circle too, who can affect mass. And Jason Wyngarde was Mastermind, all along! Still no reason to think that "Jason Wyngarde" is anything other than a pseudonym, though. I'd say it might be explicitly an in-story allusion to the actor Peter Wyngarde (Mastermind is of course picking his own face), except for the the other names.