Spark may see herself as a slave, as being owned, by Cassandra didn't. And she knew one thing. She would never work with anyone like spark. When you couldn't care for anyone else but yourself, then you wouldn't be a good team mate. So no, she would never trust nor work with Spark. Spark was everything Cassandra never wanted to be. She could feel sorrow and pity for the girl, but never anything else.
How could you bp someone who refused to help themselves?

She sighed heavily, and started out the room. She would find a way out of Vlads clutches and would do so for all of them, even if that include spark. She would honor her agreement. But she wouldn't work with Vlad. She would become a solider. Just not one under Vlad. She would make that clear, if she ever had a chance. The beatings, the punishments, no matter if they were for her or others, wouldn't stop her. No they just fueled the fire. I the end, Vlad was simply fueling Cassandra's rebellion. He never would understand that, she thought. Because he just assumed his methods would work. She snorted, perhaps it would have. If she wasn't who she was. 

She would just have to be smarter in her approach. She already knew that Adalina appreciated what she had done, and now, Lucy had experienced the help of others. So it was a beginning. But now she would have to be smarter. So she would be. 

She continued to the classroom