A window on the trailer opened and a face appeared on the far side of the screen.

"Are you sure you're ready for this?" the man asked.

"YES!" the Hollyvale Elementary School students waiting outside yelled.

"I don't think you are." But the window closed and the front door open, and a moment later, the students were climbing inside the trailer, brought by the Marine Corps Logistics Base Barstow fire department.

They climbed into the trailer and shut the door behind them. Almost immediately, the tiny kitchen filled up with smoke, and the students fanned the clouds away from their face.

After discussing the dangers of the kitchen with the firefighter inside, students then checked the living room door with the back of their hands, feeling for heat. The door was hot, thanks to heating units inside the door, and when it was opened, thick clouds of smoke billowed out, reducing visibility to almost nothing.

"The good air is down low," said the firefighter in the second room. "This is fake smoke, so it won't hurt you, but real smoke will hurt you."

The students dropped to their hands and knees and crawled into the living room. On the far side was another door and finally a descent out a bedroom window to fresh air and safety. Beyond that was a mat they would stop, drop and roll on, to complete their safe escape from a fire.

It was not their father's field day.

In fact, it was Hollyvale's 8th annual Safety Fair, and helicopters, police cars, ambulances and off-road vehicles from multiple agencies were arrayed around the school's athletic field all day on Friday as classes rotated between the stations.

"I made sure each organization had a focus this year," said Principal Matt Fedders. Students learned the international sign for choking, gun and weapon safety, basic first aid and other lessons their teachers would be quizzing them on in the next week.

"What's the number for 911?" grinned an ambulance driver for American Medical Response.

"911!" roared the students surrounding his vehicle.

"Do you guys ever call that just for fun?"

"NO!"

"Only in the case of an emergency," the driver nodded, beckoning the students over to check out the interior of the ambulance.

Part of the idea of the safety fair is to let the students know what to expect in the case of an emergency, said Hollyvale Family Resource Specialist Cindy Oliver.

"They see [the rescue workers] in their full get-up here," she said. "They talk to them and say 'if you're ever hurt, this is what we do.'"

None of which stopped it from being fun, of course.

"I enjoy this as much as the kids do," Oliver said.

Beau Yarbrough can be reached at 956-7108 or at beau@hesperiastar.com. Follow us on Twitter at Twitter.com/HesperiaStar.