During their time together, Svetlana has come to care for Sarah a great deal--to the point that Svetlana thinks of Sarah as "my child." The feeling is mutual--Sarah hasn't defined the relationship, but she doesn't object to being called that and has formed a bond closer to Svetlana than she has with anyone since her mentor betrayed her.(Unless you count the misfits, but they all got slaughtered right infront of Sarah just as she was starting to get attached. This is why I banked on the apparent time-skip in Hueco Mundo, becuase after that there was no way I could realistically show Sarah getting atached to someone else on screan I'm not a good enough writer for that.)

Caring for Sarah, educating her in how things go in Hueco Mundo, training her(to make her a useful asset to Las Noches,) and so on isn't just a responsibility she's taken, it's also literally her job for the forseable future.

She's also a Hollow.

The aptest metaphor for what just happened: Mikeal managed to simultaneously piss off a mother, a teacher, a babysitter, and a bear that is also a mother.