Michigan State University student Dominik Molotky was in class on Monday evening when he heard a gunshot in the hallway, just outside the door.

"I was sitting next to the nearest door and thank god that my fight-or-flight response kicked in because, right when that first gunshot went off, I booked it to the far corner of the class," Molotky, a senior, told ABC News in an interview Tuesday on "Good Morning America."

A couple seconds later, the gunman entered the classroom and fired "three to four more rounds," Molotky said.

"I was ducking and covering," he recalled. "I think one of the students in my class got hit."

When the gunfire stopped for "30 seconds to a minute," Molotky said, he and his classmates started breaking open a window so they could escape.

"There was glass everywhere," he added. "We broke open the window and climbed out of there, and I booked it back to my apartment."

Molotky and other students recounted their horrifying experiences as the mass shooting unfolded at multiple locations on MSU's main campus in East Lansing, Michigan.

ABC News spoke to Matt Riddle, who said his daughter Emma survived the bloodshed at Michigan State University on Monday night, 14 months after surviving another deadly mass shooting at a high school in Oxford, Michigan.

The shooting at Oxford High School on Nov. 30, 2021, left four people dead and seven others wounded.

"Having been through it in Oxford, it helped her understand what she needs to do in these situations," Riddle told ABC News during an interview on Tuesday night. "I don't like that she has those tools. I wish she didn't, but she does."

Classes at Michigan State University, which were canceled this week in the wake of Monday night's deadly mass shooting, will resume on Feb. 20, school officials said Tuesday.

Meanwhile, an on-campus vigil in honor of the victims, all of whom were students, is scheduled for Wednesday night.

"We are devastated by this tragedy and wrap our collective arms around the victims' families and friends who face unimaginable injury and loss," MSU's vice president of university advancement, Kim Tobin, said in a statement announcing the details.

Arielle Anderson, a junior from Grosse Pointe, Michigan, was one of the three Michigan State students killed in the shooting. Her family remembered her as a "precious daughter, granddaughter, sister, niece, cousin, and friend" in a statement shared Tuesday evening through her mother's employer, Comerica Bank.

"As much as we loved her, she loved us and others even more," the family said. "She was passionate about helping her friends and family, assisting children and serving people."

Anderson, who was described as "sweet and loving with an infectious smile," wanted to be a surgeon, her family said.

"Driven by her aspiration to tend to the health and welfare of others as a surgeon, she was working diligently to graduate from Michigan State University early to achieve her goals as quickly as possible," the family said.

"We are absolutely devastated by this heinous act of violence upon her and many other innocent victims," the statement added.

Interim East Lansing City Manager Randy Talifarro described Monday night's mass shooting at Michigan State University as a "horrific act of violence."

"The City of East Lansing is mourning the devastating shooting that occurred on the campus of Michigan State University tonight," Talifarro said in a statement. "Our hearts go out to all of the victims of this horrific act of violence as well as their family and friends. East Lansing and MSU have always shared in each other's victories and each other's losses. Tonight, we hold space while we grapple with this devastating loss of life together."

Talifarro also thanked the "brave first responders who quickly responded to MSU's campus."

"Against every natural instinct they ran towards the sound of danger, seeking not their own wellbeing, but instead to protect and serve those in need," he said. "And we stand shoulder to shoulder with everyone impacted by tonight's events. Please know that you're not alone in your grief. We stand with you and will be here as we seek to heal as a community."

City buildings and offices, including city hall, the public library and the district court, will be closed to the general public on Tuesday. Essential city employees will be reporting to work.

Drop-in counseling services will be available for members of the community at the East Lansing Hannah Community Center beginning at 9 a.m. ET.