Police, fire and EMS crews responded to Edison High School on Monday morning but not for an actual emergency.
They were there to help out with a simulated disaster drill.
A simulated school bus explosion kicked off the mass casualty exercise near the school's practice field.
"We have everything as realistic as we can," said Mario Gomez, a junior
More than 100 students and staff and police, fire and rescue personnel took part in the exercise.
Some very convincing drama students played the victims.
The emergency response teams were made up of students in the school's health professions and public safety magnet programs.
"We're going to put the kids in a real-life situation where they're going to be basically acting out the roles of first responders," said Phillip DeLaPena, Edison High School magnet coordinator.
San Antonio police, fire and EMS crews worked hand-in-hand with students as they tried get the situation under control and deal with victims.
Real nurses helped students in the mock triage area and real forensic investigators worked with students to pin down a suspect.
The exercise was designed to give students a chance to put into practice the skills they've learned throughout the year and they will be graded on their performances.
For Gomez, this experience let him know he's on the right carer path.
"I want to be a firefighter," he said. "Helping people giving back to the community, having that thrill in your life and it keeps you fit through all these years."
This is the first year Edison High School has held a mock disaster drill.