I think it closes the loop on the internal dialogue with what amounts to a decision by all of Pandora, not just the two subsets represented by Empathy and Chaos. If you track the sequence, when Tedd leaves, the dialogue starts as Empathy appears, followed by Chaos. What's particularly fine about this whole sequence is that it combines aspects of multiple personalities and the devil/angel-on-your-shoulders trope without being limited by either conceit. What I came away with was the sense that this is an abstract representation of Pandora's inner process, what the roiling, unstable emotional core of her looks like when it looks inward. Empathy and Chaos are not at war, they are having a discussion, indeed, they finish each others sentences at a few points. The shift back to Pandora actual at the end signifies resolution and decision in a very neat, show you don't tell you way that adds dimension and tone to what is being conveyed.