We had never heard of Perry Hall High School guidance counselor Jesse Wasmer before this week. But if there is some sense to be made of the entirely senseless events of the first day of school at Baltimore County's largest high school, it is this: Mr. Wasmer is a hero.

Students say it was Mr. Wasmer who subdued Robert Wayne Gladden Jr., the 15-year-old from Kingsville who allegedly took a disassembled shotgun and 21 rounds of ammunition to Perry Hall High on Monday. Police say the student's first shot, apparently fired randomly at lunchtime in the school cafeteria after he reassembled the weapon in a nearby school bathroom and hid it under his T-shirt, struck fellow student Daniel Borowy, 17, in the back, seriously injuring him. The second hit the ceiling harmlessly as Mr. Wasmer and others kept him under wraps until police arrived.

Mr. Gladden has been charged as an adult with attempted first-degree murder and assault. His motivations are unclear, although the possibility that he was bullied in the past has been raised (and would not excuse his actions, of course, but might at least offer a hint of his reasoning).

Even in the wake of high-profile shootings this summer in Aurora, Colo., and New York City — and in light of the various school-related shootings from Columbine, Colo., on down — this was shocking. It is one thing to read or hear of a school shooting elsewhere; it is quite another when such a terrible thing happens in one's own backyard and at a school regarded as safe and sound.

Remember when the most serious allegation facing Perry Hall High was whether the boys' soccer team showed good sportsmanship in a suggestive post-game playoff victory dance last fall? That now seems like a lifetime of innocence ago.

And what an introduction to Baltimore County for recently hired Superintendent Dallas Dance, whose first day on the job featured not only the Perry Hall shooting but a Woodlawn student injured in a serious car accident. School shootings are like a reverse-lottery — rare, but when they happen their impact on all involved is profound.

No doubt, in the weeks and months ahead, much more will be known about what happened on Monday and the actions of those involved. Mr. Dance and his staff will need to evaluate the effectiveness of the high school's response, not only for Perry Hall and for incidents involving guns but for all schools and all types of emergencies. Parents were understandably upset about how long it took for them to get in touch with their own children — although such isolation also appeared to help the school maintain order and a measure of safety for hundreds of agitated people.

What we witnessed Tuesday — a prayer vigil for the victim and a concerted effort to bring normalcy to the lives of Perry Hall students and staff and extend an offer of counseling and support to those who require it — seemed exactly right for this moment. As disturbing as the incident may have been, it was vital that students get right back in their routine and not succumb to the fear and hysteria that can so often follow such events.

But let this episode also be a reminder that guns of all types are best held by responsible adults under lock and key. A 15-year-old should no more have unfettered access to a shotgun than to a motor vehicle or stick of dynamite. The emotional turmoil that is adolescence is uncertain enough without bringing firearms or other deadly weapons into the fray. The gun in question was allegedly taken from Mr. Gladden's father's home.

All of this brings us back to Mr. Wasmer and the gratitude of the Perry Hall community toward the counselor, lacrosse coach and Perry Hall graduate who put his own life in danger. As of this writing, the simple but moving student-authored Facebook page, "Thanks Mr. Wasmer," has recorded roughly 16,000 "likes" from across the country.

In hundreds of comments posted on the site, Perry Hall students, parents, alumni and many who have little or no connection to the school offer their thanks, blessing and praise. As upsetting as the shooting may have been, the affections and admiration expressed for the selfless guidance counselor serves as an uplifting antidote, a contemporary profile in courage.