Anyway, Sara sums it all up with, "Input, output." Warrick drops the news on the skin under Ashleigh's fingernails, and Gil sums up the obvious: "She attacked herself. Ashleigh was convinced that everything about her needed to be fixed. The real problem was inside her head -- that's why she tried to fix the outside." And in the most affecting flashback of the episode, we see Ashleigh sitting down before the mirror, as in the first scene; this time, we see her face from the side, features twisted in anguish as she digs into her skin over and over. Gil explains, "Hence the digging and picking and purging and bleeding -- to us, it would be some kind of torture. To her, some sort of release." Catherine realizes that this is why Rod cut Ashleigh loose -- once she began scraping at herself, she was no longer bankable. Warrick adds that Ashleigh's malady also ignited the vendetta her ex had against Rod, and Nicky pipes up, "Yeah, he destroyed Frank's vision of her." I would have hoped that the vision extended beyond Ashleigh's surface qualities, and that the ex was also distressed over Ashleigh's personality gradually becoming subsumed by her disorder. Gil wraps up the case with, "So the victim and the killer became one and the same. The very nature of addiction, whether it be self-medicating or self-mutilating, is that the behavior we use to survive it becomes the behavior that ends up killing us."
Nicky keeps us from floating out on a moment of Zen by asking, quite correctly, how Ashleigh's eventual resting place in a shopping cart near a billboard of hers came about. And the rat -- we still haven't explained the rat. Gil answers one of our questions: "Well, the fingerprints explain that." We see Ashleigh stumble across her loft post-mutilation and collapse on her bed (why didn't we see blood on the pillowcases or coverlet before?). We then see Cassie standing over the bed, rocking back and forth in evident distress as she looks at her sister, then washing her hands so she can drag Ashleigh off the bed. Gil continues, "I think Cassie was trying to take care of her sister. She pushed her to a place where she thought she'd be safe. Where she thought she could see herself for how beautiful she really was." We flash back to Cassie wheeling (unconscious? dead?) Ashleigh over to a place where she would have been able to see the billboard of herself if her eyes had been open. Back in the office, Warrick is looking at Cassie's mug shots and a copy of Ashleigh on Dernier Cri magazine (hee! I love that name!). He asks, "What happened to these girls?" The camera rests of each CSI's face for a moment; all wear expressions of rueful contemplation, because everyone knows the answer to that question. We do not, however, ever resolve the rat issue.