(CNN) A California college student injured in the Las Vegas music festival massacre filed a lawsuit Wednesday against the hotel owners, the concert promoter and bump stock manufacturers, claiming they were all liable in the mass shooting.

The claims against MGM Resorts International, which owns both Mandalay Bay and the concert venue that hosted the festival, raise more questions about a timeline that has changed numerous times -- and, according to Clark County Sheriff Joe Lombardo, could change again. The suit also questions why hotel staff didn't notice gunman Stephen Paddock's behavior in several instances.

Specifically, the lawsuit accuses MGM of failing to respond in a timely manner to the "shooting of Mandalay Bay security officer Jesus Campos, who had gone to the 32nd floor to check on an alert from another guest room and who was shot six minutes prior to" the massacre beginning.

The lawsuit, which also names the shooter's estate and other entities, came as an MGM employee said he owes his life to Campos' heroism, and as Lombardo told a newspaper that he refuses "to say that somebody dropped the ball."

Paige Gasper's legal team, however, feels there is plenty of room for blame, but they insist that their client's lawsuit is not about a payday. Rather, it's about improving security and protocols at hotels and other venues, the lawyers said.

"If allowed, evil will find a way to hurt and destroy," said Gasper's mother, Heather Selken. "This can no longer be allowed."

Surveillance, emergency exits and advertising

Photos: Mass shooting at Las Vegas music festival Debris is scattered on the ground Monday, October 2, at the site of a country music festival held this past weekend in Las Vegas. Dozens of people were killed and hundreds were injured Sunday when a gunman opened fire on the crowd. Police said the gunman fired from the Mandalay Bay hotel, several hundred feet southwest of the concert grounds. It is the deadliest mass shooting in modern US history. Hide Caption 1 of 30 Photos: Mass shooting at Las Vegas music festival Broken windows of the Mandalay Bay are seen early in Las Vegas on Monday. Police said the gunman fired on the crowd from the 32nd floor of the hotel. Hide Caption 2 of 30 Photos: Mass shooting at Las Vegas music festival People cross a street near the Las Vegas Strip just after sunrise on Monday. Thousands were attending the music festival, Route 91 Harvest, when the shooting started. Hide Caption 3 of 30 Photos: Mass shooting at Las Vegas music festival People embrace outside the Thomas & Mack Center after the shooting. Hide Caption 4 of 30 Photos: Mass shooting at Las Vegas music festival Police arrive at the Sands Corporation plane hangar where some people ran to safety after the shooting. Hide Caption 5 of 30 Photos: Mass shooting at Las Vegas music festival A woman cries while hiding inside the Sands Corporation plane hangar. Hide Caption 6 of 30 Photos: Mass shooting at Las Vegas music festival Concertgoers dive over a fence to take cover from gunfire on Sunday night. Hide Caption 7 of 30 Photos: Mass shooting at Las Vegas music festival Police take position outside the Mandalay Bay. Hide Caption 8 of 30 Photos: Mass shooting at Las Vegas music festival A man lays on top of a woman as others flee the festival grounds. The woman reportedly got up from the scene. Hide Caption 9 of 30 Photos: Mass shooting at Las Vegas music festival Hide Caption 10 of 30 Photos: Mass shooting at Las Vegas music festival People are seen on the ground after the gunman opened fire. Hide Caption 11 of 30 Photos: Mass shooting at Las Vegas music festival People run from the festival grounds. Hide Caption 12 of 30 Photos: Mass shooting at Las Vegas music festival A woman is moved outside the Las Vegas Tropicana resort. Multiple victims were being transported to hospitals in the aftermath of the shooting. Hide Caption 13 of 30 Photos: Mass shooting at Las Vegas music festival People are searched by police at the Tropicana. Hide Caption 14 of 30 Photos: Mass shooting at Las Vegas music festival An ambulance leaves the intersection of Las Vegas Boulevard and Tropicana Avenue. Hide Caption 15 of 30 Photos: Mass shooting at Las Vegas music festival A man in a wheelchair is evacuated from the festival after gunfire was heard. Hide Caption 16 of 30 Photos: Mass shooting at Las Vegas music festival Victims of the shooting are tended to in the street. Hide Caption 17 of 30 Photos: Mass shooting at Las Vegas music festival Concertgoers help an injured person at the scene. Hide Caption 18 of 30 Photos: Mass shooting at Las Vegas music festival People gather around a victim outside the festival grounds. Hide Caption 19 of 30 Photos: Mass shooting at Las Vegas music festival A couple huddles after shots rang out at the festival. Hide Caption 20 of 30 Photos: Mass shooting at Las Vegas music festival An injured woman is helped at the Tropicana. Hide Caption 21 of 30 Photos: Mass shooting at Las Vegas music festival Police and emergency responders gather at the intersection of Las Vegas Boulevard and Tropicana Avenue. Hide Caption 22 of 30 Photos: Mass shooting at Las Vegas music festival A police officer takes position behind a truck. Hide Caption 23 of 30 Photos: Mass shooting at Las Vegas music festival A crowd takes cover at the festival grounds. Hide Caption 24 of 30 Photos: Mass shooting at Las Vegas music festival Police officers advise people to take cover in the wake of the shooting. Hide Caption 25 of 30 Photos: Mass shooting at Las Vegas music festival People tend to a victim at the festival grounds. Hide Caption 26 of 30 Photos: Mass shooting at Las Vegas music festival Police stand at the scene of the shooting. Hide Caption 27 of 30 Photos: Mass shooting at Las Vegas music festival A woman sits on a curb at the scene of the shooting. Hide Caption 28 of 30 Photos: Mass shooting at Las Vegas music festival Police are deployed to the scene. Hide Caption 29 of 30 Photos: Mass shooting at Las Vegas music festival A man makes a phone call as people run from the festival grounds. Hide Caption 30 of 30

Gasper, 21, of Wheatland, California, studies psychology at Sonoma State University and is slated to graduate next year. Before she was shot October 1 at the Route 91 Harvest country music festival in Las Vegas Village, she was on the dean's list and working three jobs, her lawyers said.

When bullets fired from the 32nd floor of the Mandalay Bay began ripping through the crowd, Gasper was shot in the right armpit, according to her complaint. The bullet went through breast tissue, shattered a rib, lacerated her liver and then exited her body, the lawsuit says.

A good Samaritan took her to Spring Valley Hospital. She's since been released and is recovering at home in California, her lawyers said.

Gasper's attorneys claim not only that MGM should have have responded more promptly to news of Campos' shooting, but hotel security should have noticed something was amiss on several occasions. Instead, the lawsuit alleges, MGM's negligence enabled one of its guests "to commit a mass shooting unencumbered."

The hotel company failed to properly monitor its hotel by failing to notice the shooter carrying weapons to his room. It also failed to notice the perpetrator setting up surveillance outside of his room, and didn't respond quickly enough after he broke the windows in his hotel room to start shooting, according to the lawsuit.

Live Nation, the festival promoter, is also named in the suit for allegedly failing to "build and mark" adequate emergency exits and train its employees how to respond in an emergency. There was no plan in place for an emergency evacuation, and no announcer took over the sound system to provide instructions, attorney Chad Pinkerton alleged.

"People were left unknowing, figuring out on their own how to escape," he told reporters.

And while the lawsuit leaves the door open to add other manufacturers and designers of bump stocks, it specifically names Texas-based Slide Fire Solutions, which is already facing one lawsuit from a gun control group . Investigators say the Las Vegas gunman had bump stocks, which are legal, on 12 of his rifles, allowing him to fire them more like automatic weapons.

The lawsuit accuses Slide Fire of "promoting the bump stock devices as an inexpensive device that could be used to circumvent federal laws prohibiting fully automatic weapons."

MGM, Live Nation and Slide Fire have not responded to CNN's requests for comments, though MGM has expressed doubt about the accuracy of the police timeline.

Pinkerton said no police departments or city officials are named in the suit because, given the facts on hand, it appears they "did the very best they could possibly do."

About that timeline...

On Monday, Sheriff Lombardo flipped the official timeline on its head . In the days after the massacre, officials said that once the gunman shot Campos through the door of his hotel room, he quit firing on the crowd below.

That wasn't accurate, the sheriff said. Campos was shot at 9:59 p.m., and the gunman didn't open fire on the crowd for another 6 minutes, at around 10:05 p.m.

That timespan will be crucial to the lawsuit: "We will never know what could've been done in that six minutes because nothing was done," Pinkerton said.

Once he began firing, the shooter unleashed bullets on concertgoers for about 10 minutes, resulting in the deaths of 58 people, yet police didn't get to the 32nd floor until 10:17 p.m. and they didn't breach the room until 11:20 p.m., after a SWAT team arrived with explosive charges, Lombardo said.

Thus, 81 minutes passed between Campos being shot and authorities entering the shooter's room. The reason for the delay is unclear, though Lombardo told the local newspaper that officers evacuated rooms before entering the gunman's suite.

In a Tuesday statement, MGM said many facts about the case cannot be verified or remain in flux, including the police timeline, "and we believe what is currently being expressed may not be accurate." A law enforcement source close to the investigation told CNN that investigators stand by the timeline, which the source described as "pretty accurate."

Speaking to the Las Vegas Review-Journal on Tuesday , Lombardo said it's "going to take some time" to sort out the details, and the timeline could change again. He refused to entertain the notion that anyone was to blame for the police response.

"You're never going to get me to say that somebody dropped the ball," the sheriff told the newspaper. "I don't believe that happened. I think everybody did a fantastic job."

As for a motive, investigators remain stumped, he said.

"We're looking for a trigger point, and right now we haven't been able to find one. And I've got to be frank with you, we may never know," he told the paper. "Something that happened in his life -- a death, divorce, loss of job, radicalization -- all those things that you would expect to find, we have not found."

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One new piece of information is that the gunman checked into the Mandalay Bay on September 25, three days earlier than initially believed. Bellmen helped take bags to his suite on two occasions, the Review-Journal reported.

"As law enforcement has confirmed, the shooter was accompanied by a bellman on two occasions in a service elevator along with his luggage. It is not a special perk and guests do request to remain with their bags, and they may be taken to their room via the service elevator," MGM Resorts spokesperson Debra DeShong said.

Paddock spent three days in a room that the casino "comped," before moving to the suite that would become his sniper's nest, the sheriff said.

He paid for the latter room himself, according to Lombardo, and traveled to his home, in a retirement community in Mesquite, Nevada, several times before perpetrating the massacre, Lombardo told the Review-Journal.

The shooter, an avid gambler, has no apparent debt, and police studying his wins and losses unearthed nothing unusual. There are no obvious mental health issues, and interviews with his family members and two ex-wives haven't yielded a reason he may have snapped. An autopsy revealed no abnormalities, the sheriff said.

"We haven't been able to point to anything yet, OK? Like I said, he's not on anybody's radar. He's not on anybody's watchlist," Lombardo told the paper.

'I owe him my life'

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Wednesday morning, a Mandalay Bay building engineer provided details on what happened after Campos was shot and the shooter began spraying bullets from his suite at the end of a hallway.

Stephen Schuck had been on a higher floor and went downstairs to investigate a report that a fire exit was jammed on the 32nd floor, he told "The Today Show."

He saw someone poke their head out of one of the hotel's inset doorways, but "nothing set off my radar," he said. It was quiet on the floor.

Schuck estimates he was about a third of the way down the hall when he heard gunshots, he said. Campos had already been shot and was taking cover in a doorway, Schuck told the morning show.

"He yelled at me to take cover. As soon as I started to go to a door to my left, the rounds started coming down the hallway. I could feel them pass right behind my head. Something hit me in the back and I took cover," Schuck told "Today."

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He pondered how to reach the wounded Campos, he said.

"I told myself, 'Wait for him. He is going to have to stop shooting sometime,'" but the bullets kept coming, Schuck recalled. "It was kind of relentless."

A dispatch recording of audio from inside Mandalay Bay obtained by CNN captures the chaos.

"Call the police. Someone's firing a gun up here. Someone's firing a rifle on the 32nd floor down the hallway," Schuck says.

"Stephen, make sure you're out of the way," a dispatcher responds.

"Stephen, security wants to know if you know a room," another dispatcher says.

"It's at the end of the hallway. Uh, I can't, I can't tell you what room. He looked like he fired down the hallway when I got close to the door," Schuck says.

Once the shooting paused, Schuck and Campos ran down the hall and took cover before the gunfire erupted again. Schuck credits Campos' warning with saving his life, he said on "Today."

Campos was resting Wednesday at his home, which is guarded by private security. He has declined to be interviewed.

Another Gasper attorney, Mo Aziz, said that though his client's lawsuit targets MGM and its security, his client is in no way criticizing Campos' response.

"It's a miracle the man's alive. I'm happy for him and his family," he said.

Schuck said he planned to return to work Wednesday. Asked how he could go back so soon to the scene of such grim violence, he said it wasn't the simplest decision.

"It's definitely difficult, but for someone to do something so cowardly and despicable, I'm not going to let that change my life," he said. "I like my career, and I'm not going to let that define me."