Jean was heavily upset she found out her father just left her which was justifiable but she was out of control due to the Phoenix Force.

"Stay away!" Jean shouts as the 'fight' commences. Kurt teleports to her trying to keep Jean on the ground as Raven and Charles look very worried.

Peter tried to get to her with his speed but Jean was too strong and pushed him aside.

Raven tried to stop Jean but something else happened.

"Stop it!" Jean out lashes and uses her mind powers to push Raven away . Making Raven get pushed into wooden spikes. Basically killing her.