"But, my dude, drinking water kills my vibe, man." She grinned at him, she was teasing him. She liked this man well enough, though she had only just met him. "I'm Gwen," she offered. "I can't promise that I won't over-indulge in fair food, but at least I helped clean your shoes first."
Because fair food was delicious and over-indulging was a given for the most part.
"...so you're an EMT," she said, stating the obvious.