Aziraphale knew he screwed up as the angel and demon were filled with tension. Standing apart from each other, staring into Crowleys sunglasses, seeing the glimpse of his upset, yellow snake-like eyes. His words were repeating in his head.

"Crowley, please. We could.. We could be together, still and.. you'd be an angel again and..—" He knew Crowley was too set on his beliefs to join him, and Aziraphale was so, so heartbroken that he had to choose. Crowley, or heaven.