how does George try to make Lennie's final moments special and free from guilt and pain?

When George emerges from the brush, Lennie is crying and admits that he did a bad thing, but George appears not to care. Still upset, Lennie goads George into participating in their ritual routine of chastisement and forgiveness - he feeds George his lines about how much fun he would have if he didn't have to look after Lennie, and Lennie offers to go live in the hills and leave George alone. Lennie then requests the coup-de-grace: the story of how they're different from other workers and of how they'll have a farm together. George repeats these monologues woodenly.

He then tells Lennie to take off his hat as he continues to recount "how it will be" for them. He orders Lennie to kneel and pulls out Carlson's Luger. As the voices of the other men in the search party near their location, George tells Lennie one more time "about the rabbits," tells Lennie that they're going to get the farm right away, and shoots his companion in the back of the head.