The girl said other employees, working at the counter, didn't see what happened next.
"He [Flowers] walks in front of me and pulls a knife out," she said. "He had his hand in his pocket, and he slowly pulled it [the knife] out like 'act calm, stay calm' that's when I put my hands up."
The 17-year-old says he forced her to the men's room, and ordered her to undress.
"He starts doing sexual things with me, and then I'm thinking of a way to get out of that situation," she said.
That's when the teen tried a gutsy trick: offering to lock the bathroom door for privacy, and when he gets distracted for a second, she saw her chance.
"He drops the phone from out of his pocket," she said. "I open the door and I ran."
Flowers has been charged with kidnapping and attempted sexual assault.
The 17-year-old victim tells ABC15 she wishes she would have done something "bold" when she saw the knife instead of going to a secluded place with the attacker. She hopes other young women can learn from her experience.
"You don't have to comply with the things they say," the teen said. "There's other ways to get out of that situation, and to not blackout, and to think fast, and to think smart."
ABC15 also reached out to the owner of the McDonald's restaurant where the attack occurred.
“Providing our employees a safe environment is one of our core values as McDonald’s owners. We are deeply upset about this incident and will continue to support the Phoenix Police Department as they complete their investigation,” said Travis Heriaud, McDonald's Owner Operator.