Originally Posted by Mr.M
I think Stryker could play a hand in that, since he will have a role in the 1970's. That's the theory I am going with.
I think The Wolverine gave that away for me. I thought about it and after seeing TW, I think a young William Stryker will be involved with Trask. At some point in the past Wolverine will encounter him and because he can't get over what happened to Jean, he intentionally kills him. It will lead to the X-men never being a Alkalai lake and her dying, or so they thought, in the first place. In doing so it will create an alternate time line in which Jean and Cyc never died.
I'll be money on it!