She doesn't react as fast as she should. The change takes her completely by surprise, and there's a split second of her brain trying to process what the hell just happened before she responds. She barely even had time to register that Tatiana is here.

"Move!" It's shouted at Kiden as Steph dives at Laura, hoping to tackle her to the ground before she can reach the other girl. If she'd given this plan any actual thought, she'd realize it would probably end badly for her, but she doesn't really consider that possibility, the most important thing right now is that those claws don't reach Kiden's face.