Uncanny X-Men, Vol. 1

Cyclops slowly recovers from Wyngarde's attack. However, seeing her lover die jarred Jean free of his control, just in time to release the helmet preventing Cyclops from using his abilities while Wolverine created a distraction. The X-Men then do what they do best: coordinate an extremely efficient attack against unprepared enemies and rout the lot. If not for the influence of the Hellfire Club, they'd stay to clean up entirely, but are instead forced to leave and allow their enemies to escape. While making good their escape, Jean's mind finally collapses on itself, and the Dark Phoenix is born in an explosion that destroys the X-jet.