david I'm trying to write an adrenaline rush and I need your help

"It took her a whole paragraph of notes before she registered that he was staring at her. Ruby's body went rigid, a lightning bolt of her own energy crackling instantly through her person. In the next moments, as she stepped inexorably backwards, she could feel adrenaline coursing through her veins, delivering power to her tensing muscles. She needed to run. It was do or die. But for just a few moments, as she stepped closer to the door of her escape, she studied that worried, curious face.

Until it smiled."