It was to be her last race of her last year of high school. Senior cross-country runner Liana Blomgren was approaching the finish line when she noticed a runner ahead who seemed to be in trouble. She had to decide quickly — pass by that runner and secure her spot as a top 20 finisher for the race, or stop to help and risk ending her high school running career with a disqualification. Blomgren didn't have to think about it for long.

That runner turned out to be 8th grader Gracie Bucher. Bucher had been hoping to qualify for the state championships with that day's race. But from the start of her run, she could feel that something wasn't quite right. Her legs felt heavy and her chest felt tight.

"I realized I was falling behind," Bucher said in an interview with her local NBC affiliate. "'I'm not wanting this hard enough, I have to keep fighting for it,'" she repeated to herself throughout the race. But with the finish line just a few feet away, Bucher's body gave out. She collapsed to the ground, pulled herself back up, and collapsed again. Bucher continued to stumble and fall over and over again as spectators — including her mother, Missy Kuntz — watched helplessly from the sidelines.

According to the rules laid out by the Minnesota State High School League, a runner cannot receive assistance from anyone — not a spectator, not a parent and not even another runner. If they do get assistance, they risk disqualification. And if that help comes from another runner, both runners are disqualified.

So Kuntz watched her daughter collapse while her fellow spectators warned her against going to her daughter's aide.

When Blomgren came along, she knew that offering assistance to another runner would earn her a disqualification. But what she saw in front of her was a runner who needed help. And so she bent down, picked Bucher up, and helped her across the finish line.

You can watch the race, including the horrifying moments of Bucher's repeated collapses in the video below. (Fast forward to around the 3:20 mark.)

As a mom and a runner, this is a tough video to watch. This isn't just a kid who got tired at the end of a run. This is a kid who is quite obviously in need of medical attention. But because of a rule, spectators, her coach and even her mom seemed unsure about offering help. Fortunately, there was a teenager there with the presence of mind to toss the rules out the window when she saw someone in need.

After the race, Bucher's parents took her to the emergency room where she was diagnosed with mononucleosis — a viral infection that causes extreme fatigue, fever and headache among other symptoms. So yeah, that explains why she collapsed during the race.

Due in part to incidents just like this one, the rules regarding aiding a fellow athlete will be changed for high school athletes, but the change won't go into effect until next school year.

That doesn't help Blomgren, who was disqualified for offering her assistance during the race. But she doesn't seemed to regret her decision.

"I don't remember what place I was in the section meet last year," Blomgren said. "I don’t remember what place I was in the section meet the year before that. But I know I’m going to remember this."