The longer they drove, the more irritated and upset Sam got. He needed to help Dean and his dumbass brother couldn't or wouldn't let him.

Sam had been doing better since the reservoir. Not great, but better. Until he lost control of his emotions. When he got pissed off, frightened or hurt, the flames licked a little closer to his field of vision and Lucifer became that much clearer.

He tried to ride it out, white knuckling the steering wheel for miles until he finally pulled off, pale and sweating. "Drive. Just fucking drive."