I remembered the exact curve in the road before the rest stop. My stomach churned, but not from fear this time. It was resolve.
"Mark, I feel sick," I said, clutching my stomach. "Really sick. Pull over at the next exit. I need some air."
Chloe turned, her face a mask of concern. "Oh dear, Sarah. Are you alright? Car sick?"
"Something I ate, maybe," I said, looking pointedly at the snack box.
Mark sighed, annoyed. "We're almost at the theme park. Can't you hold it?"
"No," I said, my voice rising. "I can't. Pull over now, or I'll be sick in your precious car."
  He grumbled but took the next exit, which led to a small, rundown gas station and diner. Not the rest stop from before. Good.
As soon as he stopped, I opened the door and got out, taking deep breaths.
"I can't go on," I said. "I'm not feeling well at all. You three go ahead. I'll get a cab or call Olivia to pick me up." Olivia was my best friend. She'd understand.
Mark got out of the car, his face flushed. "Sarah, don't be dramatic. It's probably just nerves. You've been weird all morning."
"I'm not being dramatic, Mark. I'm sick. And I'm not ruining your trip with Chloe and Ethan." I made sure to emphasize her name.
Chloe slid out, all sympathy. "Sarah, please. We can wait. Maybe some ginger ale?"
"No, Chloe. You go. Enjoy yourselves." I looked her straight in the eye. "You've been looking forward to this."
Her smile faltered for a second.
Mark was torn. His "duty" to Chloe, his annoyance with me.
"Fine," he snapped. "Fine! If you want to be difficult, stay here. We're going. Don't expect me to come back for you."
"I don't," I said.
He got back in the car. Chloe gave me one last, pitying look before sliding in beside him. Ethan just stared out the back window.
They drove off, tires spitting gravel.
I watched them go. Relief washed over me, so strong I almost buckled. Emily was safe. That was all that mattered.
I pulled out my phone. First, call my parents, check on Emily. Then, call Olivia.
As I was dialing, I heard it. Sirens. Faint at first, then growing louder. Coming from the direction Mark and Chloe had just driven.
My heart stopped. No. It couldn't be.
I ran to the edge of the gas station lot, looking down the highway. Smoke. Black smoke billowing into the sky.