Jerry can sense a very real connection between Susan and Diane. So close it leads him to believe they are sisters. What if he is sensing something so similar as to be almost identical between them that he is getting confused. Would be easy for him to be muddled up in what he feels seeing as he has not long reset himself.
Could Diane be Susan? To be exact, Susan from another dimension? Maybe her parents crossed realities, gave birth to Diane and then something happened to them, or they left her there in hopes of a better life for her?
