Sam was being sent out to grab food because Dean wanted to stick around, keep an eye on Jimmy. He wasn't sure how the guy'd react to his brother anyway... they'd just have to see.

Sam was just walking out, keys in hand and followed by Dean when they saw Jimmy out of the car. Sam was given the okay to go ahead as Dean approached him. "Whoa, hey..."

Shit, he was sick. "Hey, c'mon, you don't have that much to get rid of..."