To Leah's humiliation, she can't go! She knows she needs to, but knowing she has an audience is keeping herself from going. It's one thing to purposely use her diaper in public, but it feels even worse to try to do so and fail!
Leah fruitlessly attempts to go until it's time for them to get on the ride. Her diaper is still clean, but she has a feeling it won't be for long, without her continuing to try to use it.
Sure enough, the second the ride starts, warmth floods Leah's diaper as she pees. Near the end of the ride, as they go down the last very shallow hill, Leah's bowels empty into her diaper with an enormous fart. Leah's just glad it was near the end. The short amount of time she sits in her messy diaper on the ride is more than long enough.
When they exit the ride, Leah can feel her diaper sagging under her.
"Are you glad we didn't go to the bathroom?" Rita asks. Leah hates to admit it, but she is. It was weird and uncomfortable and embarrassing to use her diaper, but the ride was a lot of fun! She nods. "Great!" Rita reaches down and squeezes Leah's diaper. "Oh, you went both! You need a change bad, sweetie."
"Yes, I do," Leah agrees. She can't wait to get out of this diaper, into a fresh one, and get back to having fun at the park.