Two women go away together. One meets a man that distracts her from being there for her friend. The betrayed friend says, "One day you will need me, and then I won't be there for you." When they next go away together the roles are reversed, the threat becomes reality. But the two situations are not exactly the same - the man in the first scenario was benign, the man in the second scenario is toxic. That and other differences displace the parallel between the two events.—fetsiboomsticks