In the novel Llewellyn has Chigurh dead to rights…
And lets him go.
In the hotel scene, when he discovers the transponder, he doesn’t hop out the window after blasting at the door, instead he hides in the corner, and allows Chigurh to walk in the room.
He has Chigurh dead to rights, with gun drawn and his back turned, orders Chigurh to drop his shotgun, which he does, and Llewelyn walks out the room and hauls ass down the stairs, out the door, and is then shot like in the film.
In another life maybe Chigurh gives Llewelyn a pass as he does spare his life more or less.