His confidence is transformed by the crowd’s response.
Scotty is described as being a "quavering husk...just moments before." This shows his lack of confidence and anxiety about being on stage. Once the crowd's enthusiasm and excitement for his performance reached him, it is described as "lifting him off his stool...unleashing something strong, charismatic, and fierce." This change in his demeanor shows his confidence grow in response the crowd.
Textual evidence is used to add credibility to a claim or argument. It shows people how you came to an answer.
