The plaintiff in the case, Paige Gasper, a 21-year-old student at Sonoma State University in California, was with a group of friends the night of the shooting, when she was shot in her right underarm. After she was trampled by others trying to escape, another concert attendee took her to a truck that raced her and a group of other people who had been shot to a hospital. She was the only passenger who survived, according to the lawsuit. After being treated for fractured ribs and a lacerated liver in an intensive care unit, Ms. Gasper returned to her family in California, where she is still recovering.

The lawsuit claims that MGM Resorts “breached their duty of reasonable care” and failed to keep the hotel “in a reasonably safe condition” because it did not monitor people coming into the hotel and did not respond quickly enough to Jesus Campos, a security officer whom Mr. Paddock shot and wounded about six minutes before he began firing on the concert crowd. It also says that MGM, which also owns the concert venue, and Live Nation did not design, build or mark adequate emergency exits and failed to “properly train and supervise employees in an appropriate plan of action in case of an emergency.”

“We live in a new normal and the music and associated entertainment industry has seen a tremendous boom,” said Nathan Morris, the lead lawyer in the lawsuit. “In today’s world the old protocol doesn’t work. At one of these huge venues the safety protocols clearly have not caught up with the notoriety and popularity of these events. Paige wants things to change. She wants to go to the next country music festival and not be freaked out when the fireworks come on.”

A spokeswoman for Live Nation declined to comment on the lawsuit. Debra DeShong, a spokeswoman for MGM Resorts, said she could not comment on the lawsuit but said that “security has been and continues to be a top priority at all of MGM Resorts.”

There have been at least two other filings in Clark County over the shooting: a class-action claim from the Brady Center to Prevent Gun Violence against the manufacturers and sellers of bump stocks in Nevada, as well as a petition asking the court to take control of the estate of Mr. Paddock, the 64-year-old gunman who shot himself in the head after the shooting.