A 20-year-old college student and musician was injured by an errant bullet fired from the apartment next door into her bedroom this week.

Daria Tolokonnikova, who lives with her grandmother in downtown San Diego, was sitting on her bed studying just before 7 p.m. PT (10 p.m. ET) Tuesday when without warning she was knocked out of bed and collapsed onto the floor, bleeding from the back of her head.

“I started blacking out. Everything immediately blacked out. I fall down on the ground for a second or two,” Tolokonnikova told NBC 7, an NBC News station in San Diego, on Thursday.

The round ripped through the drywall between the neighboring apartment and embedded in the wall opposite, according to footage from the scene where two holes are clearly visible. Remarkably, the bullet had only grazed Tolokonnikova’s scalp, which required stitches in hospital.

The incident has left her too scared to sleep in her own room.

“I am scared right now to go to my room. I am just very scared to go to my room. When I hear some noises, I get terrified,” she said.

According to a police report shared with NBC 7, the 9 mm bullet was allegedly fired by Marine Corps Cpl. Samuel C. Hernandez, 22, who was arrested on suspicion of negligently discharging a firearm and later released on bail.

The police report said Hernandez, who is assigned to Marine Aircraft Group 41 based at MCAS Miramar, was practicing his gun handling skills, NBC 7 reported.

“I was practicing my dry firing of my pistol. It was a Glock 19 handgun that I own. I was being stupid and put my finger in the trigger and played stupid games. I was aiming at the wall,” the suspect is quoted as saying in the report.

He is expected to face a judge later this month.

NBC News has approached the San Diego Police Department for comment. NBC 7 contacted Hernandez’s unit at Marine Corps Air Station Miramar, north of San Diego.

Tolokonnikova, also a classical pianist and singer, studies at San Diego City College and lives in the city’s Gaslamp District. She underwent several X-rays and tests and sent home after her wound was stitched.

“I would understand that it could happen with anybody but not the guy who is professional, who is in the military and was playing with a gun,” her grandmother, who asked not to appear on camera, told NBC 7.