I can only assume that "S" deliberately tipped that other girl off because she didn't like that Young had become complacent in her assignments, and wasn't treating them with enough care or attention to detail; like instead of moving that last 'assignment' directly as was told, instead Young left it in her bag to handle later. I get the feeling that we're still in the 'set up' phase of this story, despite all that has happened so far. One thing that I've been having a hard time wrapping my head around is, why hasn't Young confided with any of her friends; does she not see them as friends? The more this goes on, the more I feel that Young herself is meant to be or treated as an allegory.