Even criminals have principles. Ever hear the expression "honor among thieves?" It's why Mr. Blonde didn't rat on Joe even though it meant four years in the slammer. Loyalty has always been the first commandment of mobsters; you violate it at your peril.
The six guys in Reservoir Dogs are all loyal to Joe, but they don't know anything about each other. They're working closely together on this heist without really knowing who to trust. When it becomes clear that there's a rat, all loyalty bets are off.
Questions About Loyalty
How can criminals like these guys, who seem to have no scruples about robbery and murder, or even concepts like loyalty?
How does a crime boss like Joe inspire loyalty?
How does Tarantino manipulate the audience's loyalty to the characters? Do you think the viewers' loyalties shift as the movie progresses?
Chew on This
Loyalty among criminals isn't based on feelings or relationships; it's just enforced behavior to make sure the criminal operations can be successful.
At the end of his life, Orange had seriously divided loyalties.