Jean follows Eliot, making sure that every step he takes matches the other man's path. However, when Eliot speaks of his concerns about his mental state he has to stop on his tracks and let out a fast, short breath that may or may not be laughter.

No, he won't start an argument about who is hallucinating whom. He can well predict Eliot's reaction if he tries.

"Have you any experience with those?" he asks airily, resuming his careful walk. "Going batshit? Visiting other worlds?"

As far as Jean is concerned, there is no difference between those two. As much as there is no difference between the wild landscape before his eyes and the random voices in his mind.