She stalled the old Bus and the beginning of this part is her trying to get it started again. She’s aggressive on the pedal because she’s at a stop sign and doesn’t want to block traffic. Her barefoot is just going to town on the gas as she’s repeatedly begging the car, “Come on baby…come on baby!” She bursts out laughing as the engine finally roars to life — it’s the only way she can contain her embarrassment.
She gets going again, driving the bus hard and making the engine scream!