(CNN) -- What do you do when terror comes to your hometown? When it walks down your school hallways and into classrooms, wielding two kitchen knives? When it leaves behind pain, suffering, chaos?
If you're students and staff at Franklin Regional Senior High School, you act.
Wednesday's violent spree at the suburban Pittsburgh school ended with 20 students and one adult with stab wounds, according to police. Yet even as one doctor from Forbes Regional Hospital in nearby Monroeville described some of their injuries as life-threatening, another from the same facility said he expects all the victims to survive.
The fact that their prognosis wasn't worse and the fact that there weren't more victims are tributes to an assemblage of people who made a difference in ways big and small.
These people stepped up in the face of confusion and terror to help each other, doing everything from pulling a fire alarm to tenderly nursing victims' wounds, to subduing the alleged attacker, Alex Hribal, 16, to now rallying to provide comfort to their neighbors.
As Pennsylvania Gov. Tom Corbett said, "There are a number of heroes on this day."
Hoodies become makeshift tourniquets
To the vast majority, it was just the beginning of another day at Franklin Regional Senior High in Murrysville, a small city of 20,000 about 20 miles east of Pittsburgh. A little over a week before the start of an abbreviated spring break. Just under two months from the end of the school year.
Very quickly, things changed.
Student Mia Meixner recalled "a commotion behind me," then saw one boy on top of a freshman, stabbing him.
"And the freshman boy stood up off the ground, and he lifted up his shirt and was gushing blood from his stomach all over," Meixner told CNN. "It was very terrifying."
Three students helped this victim, trying to take him to a nurse, according to Meixner. But he wasn't the only one: Meixner spotted a girl with her arm "gushing blood" and herself offered to help.
A teacher then approached, as did a flood of people running down the hallway screaming, "Get out, run! He has a knife."
It was then, Meixner recalled, "The teacher said, 'I'll take care of her. You can run.'"
This was one of many school staff -- from cafeteria workers to aides to administrators -- who made helping the wounded a priority even with the danger still on the loose.
Matt DeCesare, another student, saw teachers pulling students outside to safety. Some had the idea of asking for everyone's hooded sweatshirts, which they fashioned into makeshift tourniquets to stem the bleeding.
"The teachers kind of blocked the students (from view) because it was not good to look at," said DeCesare. "But from what I could see, that was very effective."
Crying while trying to keep victims conscious
Sometimes, heroes became victims.
That's what Gracey Evans said happened, when she saw someone running down the hall with knives.
"My best friend stepped in front of me, and he got stabbed in the back," Evans told CNN's Anderson Cooper. "And then, in 30 seconds, I saw (two other) people get stabbed."
All three -- including Evans' protector -- "collapsed on the floor." Evans yelled, then followed a teacher's instruction to get inside his classroom, along with the three nearby victims and three others.
Her best friend was on his stomach while Evans set down one of the most severely injured and -- with the help of friends who got her paper towels -- applied pressure on his wound. She cried "the whole entire time," all the while trying to talk to the victims to keep them conscious.
"I was keeping him conscious as long as he could," she recalled. "He started coughing and he barfed, and I couldn't take the smell."
As to what happened next, Evans recalled: "That's when a bunch of blood came out of his wound, and I couldn't take it anymore. And so I stood up."
Thankfully, almost as soon as she got up, EMTs rushed into the room.
But Evans wasn't done. She grabbed the hand of her best friend, then "screaming in pain," and "he wouldn't let go the whole way to the hospital."
She ended her interview with CNN with a message: "Brett, if you're listening to this, I love you and I hope you're OK. And I also want to thank all the people that were helping me.
"I wasn't alone in this."
Assistant principal tackled suspect
The horrific ordeal was over in about five minutes -- not that it ended easily or quietly.
Assistant Principal Sam King managed "to tackle the suspect," said Murrysville Police Chief Tom Seefeld.
He did so after seeing the alleged assailant stab Sgt. John Resetar, a school security guard, in the stomach, according to a criminal complaint.
The school's other assistant principal, Joan Mellon, also played a role in subduing the 16-year-old sophomore, who was ultimately led away away with minor injuries to his hands.
And school resource officer William "Buzz" Yakshe was involved from beginning to end, from alerting police by radio about the chaos to being one of the stabbing victims to ultimately handcuffing the suspect.
Dan Stevens, an emergency official with Westmoreland County's public safety department, said later that Yakshe was "doing fine."
"He's more upset than anything else over what happened, because these are his kids," said Stevens.
'Be around and be present'
"Those four individuals (and) courage" helped bring an end to the violence, Westmoreland County District Attorney John Peck noted.
But it did not mean an end to the anguish and agony.
This pain was most obvious in hospitals around western Pennsylvania, where the wounded were treated for injuries to torsos, abdomens, chests, backs and limbs, including two victims who were rushed into surgery.
Even those not wounded physically suffered. Whether they witnessed the bloodshed directly, knew people who did, or just tried to make sense of what happened, it won't be easy to turn the page.
"It feels really surreal," said Meixner, the Franklin Regional Senior High student. "...You never think it's going to happen at your school. And I'm really mind-blown by it."
Getting her and other students through this ordeal now becomes the task of other "heroes," authorities said.
They might be parents offering a shoulder to cry on, counselors brought in to lend their expertise, or strangers offering a smile or a prayer.
As Dan Hertzler, a pastor at Cornerstone Ministries in Murrysville, said, none of these people will have "all the answers." But what they can do is be there for each other, much like fellow students and staff at Franklin Regional Senior High were there for the wounded on Wednesday.
"The biggest thing right now is really just to be around and be present," Hertzler told CNN. "Many of these students just need to feel the love and safety of their family and friends, to be able to grieve with the community."
CNN's Steve Almasy, Ashley Fantz, Chelsea J. Carter, Dana Ford, Pamela Brown and Mary Kay Mallonee contributed to this report.