Some might ask what’s up, with the shootings in Colorado, Wisconsin and now a school shooting in Baltimore on the first day of school.

Maybe we’re hyper-sensitive to mass violence. Maybe there’s something in the air. Maybe it’s the current political environment where people argue and attack, seemingly without provocation.

What’s really at work here is what has been at work. Violence can occur at any time, anywhere. What is your response. People who have studied mass attacks say your options are few, especially when you are less-well armed and less-well prepared than James Holmes or Wade Michael Page.

The city of Houston did a big service with its video Run.Hide.Fight. Those are your options. First run away. Second, if you cannot run, hide from the attacker. Third, when those first two fail or aren’t available. Fight.

In Baltimore, the 15-year-old student was stopped by a teacher. That’s generally the case, according to the consulting firm Hard Tactics, which discovered in a review of 40 mass attacks that citizens stopped the killing in 17 of the 40 incidents. Police response, while better and quicker, can’t get there faster than a person absolutely determined and motivated not to be a victim.

Student Critically Wounded on First Day of School, Teacher Subdues Gunman

By JENNIFER ABBEY and ANDY FIELD | ABC News – 3 hrs ago

A 17-year-old student is in critical condition after he was shot on the first day of school today in a Baltimore suburb and a quick thinking teacher subdued the teenage gunman.

The alleged shooter was another student who was 15, Baltimore County Police Chief Jim Johnson said. The suspect was arrested, Johnson said.

The school, Perry Hall High School, was evacuated.

The 15-year-old student, whose name was not released, walked into the school cafeteria at 10:45 a.m. and fired one shot, the chief said.

A student described the weapon to ABC News affiliate WMAR as a shotgun. Police haven’t confirmed the type of weapon used.

A teacher grabbed the boy with the gun and wrestled him against a wall, holding the gun away from the shooter. A second staffer, a school resource officer, was outside the cafeteria and rushed in to help the teacher subdue the suspect until cops arrived, police said.

“One student has been shot and is being taken to the hospital by medevac,” the Baltimore County Police Department said in a statement.

The school is located in White Marsh, Md., northeast of Baltimore.

Students were evacuated to the Perry Hall Shopping Center where frantic parents went to be reunited with their children there, according to police. Students are also being bused home from the middle school across the street, ABC News affiliate WMAR reported.

It was the first day of school for students. Several roads in the area have been closed and the school is on lockdown, according to ABC affiliate WMAR.