JMO - BPD, a complex condition, is between mistrust of others and horrible self-esteem. There are some interesting studies indicating BPD lying in the intersection of three other well-known conditions. Maybe in five years we shall have a better understanding of what it is.
But my inner image of an ideal borderline girl would be not a “difficult” person, far from it. On the contrary, she is very nice, very polite, exceptionally attractive if on the slim side, always perfectly dressed and groomed, at this, she is also very smart and is “a helper”. She is often a loner in the college but gets perfect grades…and suddenly she falls apart and leaves when there is just one year left to graduate. And then she’d transfer and do great, and then fall apart several months shy of graduating again. This constant self-sabotaging on the verge of success is very common for BPD, IMHO. Either they get tired of pretending to be perfect, or this perfection is a shield, covering the fear of someone seeing “the real her”, or maybe success would put them right into the limelight and they don’t enjoy it.
This is why, if we are thinking Lucy and BPD, Münchausen syndrome is a little bit off that track. Münchausen syndrome would be probably more typical for histrionic personality disorder, another cluster B trait. Histrionics love attention and love to be in the center of attention. Borderlines, not quite.
I don’t quite know where I am driving at… some intuitive path about Lucy who I think is borderline. Very secretive. Prone to splitting. Her note was an example of splitting too. But maybe “splitting” refers not only to the external world, that’s either “all good” or “all bad”. Maybe it could be applicable to self-perception. Maybe the more she tried to look “nice and kind” in the eyes of everyone else, the more she had to balance it by “being horrible”? And when doctor A appeared, she had to try harder to be the best…and it pushed her more to be “horrible and murderous” when no one saw her”?
ETA: This phrase “I killed them on purpose because I am not good enough to care for them” is the example of splitting IMHO. The better she looks in the eyes of the world (and she does, she is a band 5 NICU nurse, the ultimate helper, plus the face of the unit in 2012, and the parents are thankful, too), the harder to keep the facade, and then she secretly does something horrible to prove to herself that she is not “good enough”. And then she can keep up with being “Mrs. Perfection”.
Does anyone see it this way?