(CNN) - Call it coincidental or a call for alarm: Two teachers in two states killed at school days apart, each allegedly by a student.
The nation is searching for meaning and answers after teacher slayings in Nevada and Massachusetts this week. And an education firm says the crimes are the latest examples of how educators feel schools are less of a traditional haven, especially from gun violence that killed one of the instructors.
A survey of 10,600 educators in 50 states captured this uneasiness after another school shooting -- in Newtown, Connecticut -- when the vast majority of respondents favored an armed guard to improve safety, though they didn't want to be armed in school themselves. Almost a third of teachers felt that their school wasn't safe from gun violence.
"That's a high number to me. That's a lot of teachers feeling nervous about this," said Cory Linton of the School Improvement Network, which provides professional development to educators and which conducted the January survey.
"Even though nine out of 10 educators feel safe in school, the survey shows that teachers don't feel completely safe from random acts of violence," said Linton, executive vice president of the Utah firm. "You think about how many students are in Massachusetts and how many students are in Nevada. They're not going to learn much this week. That's a pretty high cost to society."
As a sign of the times, 43-year-old Linton cited how the only drill he did in school was for earthquakes. Now, his five kids must learn a "lockdown drill" in school in the event of a violent intruder or bomb threat.
In one remedy to this specter of violence, some teachers carry a "panic button" that turns on a video camera in the classroom that transmits live footage and audio to police, Linton said.
"I would call it an emerging trend. It's still new," he added.
After the Connecticut school shooting that killed 20 children and six adults in December, more than two-thirds of schools added door locking systems, security cameras, lockdown procedures, part-time guards or police patrols, the survey found.
"It's sad that we even have to these conversations, that we have to talk about armed guards in schools," Linton said.
Police say a 12-year-old boy gunned down a teacher Monday in Sparks, Nevada, before killing himself, and a 14-year-old boy was charged Wednesday with murder in the slaying of a high school teacher in Danvers, Massachusetts.
In the Nevada shooting, two students also were wounded.
In the Massachusetts school violence, student Philip Chism has been charged with the murder in the death of Colleen Ritzer, 24, who went missing Tuesday. Chism allegedly used a box cutter to kill her, two law enforcement sources close to the investigation said Thursday. He was enrolled in her math class, authorities said.
Chism brought the box cutter to school and allegedly killed his teacher in a school bathroom, one source said. He allegedly rolled her body out of the building in a recycling bin and dumped her in the woods nearby, the source said.
The two law enforcement sources say Chism changed his clothes after killing the teacher.
Meanwhile, in Washington state, an 11-year-old boy brought a handgun, knives and 400 rounds of ammunition to his middle school on Wednesday. There were no injuries and no shooting, but the boy was arrested and now faces an attempted murder charge, said police in Vancouver, Washington.
The school violence has incited a robust dialogue in social media and among experts, and much of it focuses on safety.
"We expect the national conversation about school safety will be heightened, but the fact remains, most school campuses are still among the safest places students can be," the Nevada State Education Association and the National Education Association said.
"Nevertheless, NEA and NSEA will continue to advocate for stronger measures to ensure the safety of students and school personnel so future tragedies can be avoided," the teacher unions said.
Parental organizations agreed that better school security is needed.
"National PTA is hopeful that this incident will persuade the nation to make meaningful changes to protect all children," the group said about the Nevada shooting. "It is critical that we work together to find the most effective ways to ensure that all students have a safe environment in which to thrive and learn."
But psychologist Jeff Gardere said schools are no longer the safe havens they used to be. And he pointed to a disturbing reality among younger Americans.
"How does this happen with someone so young?" Gardere wondered of the suspects.
"I don't think we should get into the mindset that these sorts of crimes are committed by someone 18 years old and up," he added. "We need to understand that severe emotional issues can happen in someone very young."
How to deal with these issues -- and make schools safer -- was discussed bluntly and candidly in social media. On CNN's Facebook page, Wednesday's arrest in the Massachusetts teacher's death was the most commented-upon story of the day.
The remark that provoked the most debate was a simple statement by Ryan J. Judson: "The problem is the lack of God."
Some agreed. Some disagreed. What they had in common was how strongly they felt.
"I guess bad things never happen to people that follow god then," Donald Burkett wrote.
Another commenter took a less metaphysical approach.
"What the hell is wrong with this generation???" wrote June Marie Cariello-Izenman. "What r they learning at home???"
One commenter replied, "More like, what are they learning from their friends and/or internet..."
"They are not learning anything and are being told it is OK to have no moral compass by the school systems they spend more time with than their families," said Patrice Cassidy Ripley.
Conservative commentator Ben Ferguson favored arming teachers who are interested in going through gun training to defend their schools, faculty and students. He cited how some teachers already have military and law enforcement backgrounds.
"We hear about teachers using their body as a human shield," Ferguson said. "If that guy is willing to use his body as a human shield, I trust him to go through training to carry a gun.
"I don't want every teacher to be armed," he added.
Others urged a measured, temperate response.
Bishop Dan Edwards of the Episcopal Diocese of Nevada noted how "all of us are personally affected when violence erupts in a school, which of all places should be safe for children, a place to learn and grow."
But he urged prayer for the town of Sparks and asked that the public "consider deliberately and compassionately what we can do to keep our children safe."