The classrooms were empty, and the hallways were quiet.
Suddenly, an armed man began hollering at the end of one corridor.
Port St. Lucie police confronted the suspect and took him down, as teachers went screaming past.
It was all part of a drill as police have spent several weeks engaged in active shooter training where every second count.
“Ever since Columbine changed the way we do everything. Not waiting on SWAT, we don’t have that time," said Training Coordinator Officer Scott Johnson.
This is a two-part operation. First, police neutralize the threat. Then, fire rescue is brought in to treat any victims.
“There’s formation we have to learn and communication back and forth. That’s the biggest key learning how to communicate. We’re learning that they’re protecting us while we’re doing the job of saving lives," said Captain Charles Chandler with the St. Lucie County Fire District.
For the staff at Renaissance Charter School, this is also about being proactive.
“It’s very important for us to prepare not only mentally but physically and look at our safety plan and look for holes to ensure our students are safe," said Principal Christiana Coburn.