RNA - Duaa Ahmad, a senior at Oshkosh West High School, is seen in the footage ushering her classmates in to the Ahmadiyya Muslim Community's Oshkosh chapter mosque, where she is a member.
Ahmad told ABC News that she “felt a little fear” but she felt like it “had to be done."
The mosque is across the street from the high school, where police said an armed student stabbed a school officer during an incident before being shot by the officer.
Both the student and officer were treated at a hospital for non-life threatening injuries, according to police.
Ahmad said a teacher told students to run from the campus minutes before the incident, but they had no idea why.
"It could have been anything. That fact that we didn't know caused even more anxiety," the Muslim teen said.
"I'm lucky that I was in that place when that situation ensued, and I'm just grateful that I was able to enter the code and let as many people in," she added.
According to Press TV, in a post on its Facebook account, the Oshkosh Ahmadiyya Muslims group praised Ahmad for her quick thinking and said, "our doors are always open."
It was the second shooting to take place in a high school in Wisconsin in two days.
The shootings, both involving resource officers, have sparked a renewed debate about gun violence and the role of armed teachers or police in American schools.
Tony Evers, Wisconsin's Democratic governor, called the incidents “breathtaking and tragic”.
There has been an average of one shooting per week in schools across the US this year.