With how Jonah is with choice, with decisions, with seeing every threshold and knowingly to stepping through them to see what’s on the other side, I think he would get a kick out of making his new bodies choose their fate.
The thing is, it’s easy: Carve out your own eyes, and The Eye will replace them for you. You will become an incarnation of the It Sees Me, your blindness will be cured and you will see all that it Sees, and you will realize how truly blind your own sight was.
Jonah has led them on the path of conversion, they have become a new but devoted follower of their god. They know, they Know, enough to know the truth of Jonah’s words. But he’s kept them carefully fed, so used to enjoying the best cuts that they don’t crack open bones and dig into the marrow to get every last drop. They Know what Jonah says is true. They Know Eye will grant its Incarnation near immortality.
But they don’t understand. Not yet.
(When their new eyes are in place, they do. They fully and completely understand where their choices led them. Just as Jonah promised.)