LORELAI: Oh, hey, look, new bag boy.
RORY: Oh yeah, that’s Marty. He’s subbing for Dean while he’s out of town.
Dean is suddenly visiting his grandmother out of town in this episode – doesn’t he have to attend school? Considering how upset Dean was at the end of the last episode, it’s possible he has gone to stay with his grandmother to have a break from Stars Hollow and Rory, or to think things through.