When Noelle Newton started her career as a counselor a decade ago, back-to-school preparations meant decorating classrooms and reviewing procedures for the after-school pickup line.

But on Wednesday afternoon, she prepped for the start of the new school year by learning how to barricade a classroom door while an "active shooter" — actually, another teacher with a Nerf gun — tried to force her way in. In the next drill, Newton and the other teachers threw tennis balls, symbolizing staplers or books, to try to stun the mock killer.

"It's sad, really sad," said Newton, who works at Marple Newtown's Loomis Elementary School in Delaware County. But she said she's glad she's prepared because the threat of violence is "something that scares me every day."

From breaking a choke hold to stanching the blood from a gunshot wound, the two-day Teacher Safety Workshop offered up a realistic if unrelentingly grim glimpse into threats increasingly faced by America's teachers in the post-Parkland era. The workshop drew about 75 educators and was sponsored by Delaware County District Attorney Katayoun M. Copeland and state Sen. Tom McGarrigle.

Schools throughout the country recognize that ID badges are no longer enough to protect students and teachers from the once-unthinkable. With 23 school shootings already recorded in 2018, students returning in September will encounter more armed guards and surveillance cameras, wire fences and metal detectors.

In addition to beefing up security, schools are stocking up on emergency medical trauma kits, and some have purchased protective shields that fit inside a backpack and can stop handgun bullets or a knife attack.

At the workshop, at the Penn State-Brandywine campus in Media, attendees learned not only how to duck for cover and how to fight back against an active shooter, but also how to act like a crazed mongoose – in the words of one detective — to ward off an attacker who might be a violent student or even an angry parent.

"Teachers didn't sign up for this, but, unfortunately, this is what they need to do," said Louis Gentile, director of safety for Upper Darby School District.  In his session, Securing and Defending Your Classroom, Gentile gave tips on how to break a classroom window with a chair (go for the upper corners) and how to arrange the classroom with hiding places that are ready to go.

"Time counts," Gentile told the teachers.

The seminar reflected what could be called the new realism that's taken hold among educators in the aftermath of the death of 17 people at Marjory Stoneman Douglas High School in Parkland, Fla, in February, in which school shootings and other outbreaks of violence aren't seen so much as anomalies but as events to prepare for.

"We don't have the luxury of living in an ivory tower or burying our head in the sand when it comes to the risks our nation faces regarding school safety," said Copeland, who urged "a proactive rather than reactive approach" to violence in her opening remarks.

Many of the teachers who attended struck a similar note, saying they hated this new normal but they needed to be prepared.

"You don't know the situation that you're going to be in — it could be an irate parent at a meeting," said Andrew Kane, a teacher at Marple Newtown High School. He said when his career started 20 years ago, "it was a safe environment. You didn't worry about anything. Now you have to worry about your safety as well as your colleagues  and students."

Several teachers were more afraid about the potential for an isolated act of violence than a mass shooting. Patricia Alford, an administrator in the Southeast Delco School District, said her scariest moment happened two years ago when a stranger approached her in the parking lot where she works, asked her for a ride and, when she refused, started pounding on her car window.

"What today did," said Alford after completing the Personal Defense Tactics class, "is give me some options if I didn't get to my car."

Another session, Conflict Management: Initial Contact, offered ways to ensure that an angry or unpleasant conflict doesn't escalate. Teachers also learned about available mental-health services, the inner workings of Delco's Juvenile Court, and how to control bleeding before emergency crews arrive.

But if those techniques fail, District Attorney's Office detectives Steven Bannar and Anthony Ruggieri were there to teach hands-on defensive tactics — including a strike to the throat that could be lethal, a forehead butt to the nose for someone trapped in a body hug, and the proper technique for kneeing someone in the stomach or groin.

"It's the mongoose principle — no one wants to fight with a loony person," Bannar told a group of a dozen teachers as he advised them to wildly swing their car keys at an attacker. "People think you're teachers, nice passive people, an apple on the desk. … You have to act like a crazy person."

The detectives ran through more than a dozen maneuvers that teachers could use to defend themselves and stop an attack. "The worst time to figure out you can't fight," Bannar said, "is in the middle of a fistfight."

Gentile's workshop on defending the classroom was focused on the issue that gets the most attention: dealing with an active shooter. He told the teachers that learning to be more aware of one's surroundings, recognizing when something seems not right, and knowing how to react to the sound of gunfire can be "an empowering moment."

If all else fails, Gentile told the teachers, it's important to fight back with anything that's at hand: staplers, textbooks, a laptop. "Passive targets," he said, "is what we're trying to avoid."

In a couple of weeks when the bell goes off to start the school year, some advice from Bannar may still be ringing in teachers' ears.

"You're not going to school to get beat up," he said. "You're going to school to educate. Unfortunately, in today's society, people are insane."