[ There is a reason why Erik doesn't want Charles to see those memories. Well, several reasons, atually, but there is knowledge of loss behind that door that he doesn't want Charles to suffer through before he has to. Even the ways in which he changed, perhaps pushed to a limit in his own mind, led astray by his own goal of coexistence, to the point of putting his own people at risk.

It was difficult. They were all pushed to their limits, and with Raven's death...

And to Charles, Jean's loss on top of that. ]

No. [ Not that he needs to answer when Charles knows it already. ] It's still well in your future, and right now— it might not even come to happen to you. We don't truly know what happens now that we've been brought here.

[ Charles might go back to create an entirely different timeline, or they might not go back at all. They might go back and everyone is dead and gone. Erik has probably run all the worst case scenarios through his head at this point. ]