An armed school intruder and people hiding under desks — it’s a scene we've become all too familiar with, but this scenario is not real.
Instead, it's been carefully planned in order to help first responders learn how to react in the most dangerous and difficult situations.
The Irving Police Department helped set up and participated in Saturday's drill.
"The SWAT officers will have to move through the school and assess those threats, neutralize those threats,” explained police spokesman Officer John Argunaniz. "And at the same time, they will encounter casualties that they will also have to assess and move along."
This "active shooter" drill is different from previous exercises, because other drills were being held at the same time in Irving and across North Texas.
The entire exercise is called Urban Shield, and it spanned 16 counties. The drills include police, firefighters, paramedics, and others. The crews have to work with teams from other cities to coordinate people and resources.
"What we've learned is a lot of these critical incidents require multiple jurisdictions to work together," Argunaniz said. "So this gives us an opportunity to see where we are and what we can improve on."
In Fort Worth, urban search and rescue crews trained on things like trench rescues, and even saving people caught under a building and an overturned truck.
Multiple past disasters have helped first responders learn to communicate better through radio transmission, but Saturday's training went one step further.
“Two actual teams working side-by-side,” said Steve Coffman of Texas Task Force Two and Dallas Fire-Rescue. “We call it 'boots on the ground.' Can they work together? Can they coordinate command and control? Can they coordinate the strategy to conduct the rescue?”
When it's all said and done, all the first responders taking part will go over every detail and document what works and what doesn't when every second counts.