It's interesting that he says "why is it OUR job to save everyone"... no longer the Sam who has never hunted. All because he's trying to convince Dean to stay.
SAM Dean, you're drunk. You're drunk-dialing me. DEAN I am not drunk. Quit screwing around! SAM Look, it's late. All right, just get some sleep and, um, I'll ... see you tomorrow. OK? DEAN Wait, Sam! Sam!