Perhaps their biggest concern was whether they would win the Madden Tournament in Jacksonville, Florida, and get the chance to compete in Las Vegas for the big prize money.
But just as a game started, real gunfire erupted. The victims scolded in pain. And these sounds were streamed live online for game fans to hear.
Attendees gathered at the Jacksonville Landing Complex, an open-air marketplace with shops, bars and restaurants along the St. Johns River
David Katz, a 24-year-old player from Baltimore, Maryland, was in town for the tournament in GLHF Game Bar, behind a pizza restaurant. On Sunday he brought a gun into the venue and opened the fire, killing two people and injuring nine others. Then he turned the gun on himself, said Jackson Williams sheriff Mike Williams. The police have not released a possible motive.
Two people were injured, fleeing the area, Williams said. The victims are in stable condition in the local hospitals, the sheriff said.
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People screamed. One person exclaimed, "Oh f **, how did he shoot me?"
Within two minutes, the officers were on site.
Rya Aleman said he had crouched in the bathroom for 10 minutes and ran away from the scene.
"I'm still shocked, I can barely talk," he told CNN.
Fire Station Training Nearby Responds
Seven members of the Jacksonville Fire Station 1 – known as "The Rock" – completed a routine training course in a parking garage across the street as Randy Wyse, the president of the Jacksonville Association of Fire Fighters, came ashore when dozens of people came out,
a person pulled up her shirt and showed where they had been shot in the chest, Wyse said. A second person with gunshot wounds followed shortly thereafter.
When four firefighters made first aid, three more ran to the landing site, Wyse said, and led a policeman.
They started treating people and found the three victims including Katz's body.
Hours after the shootings, the authorities said, agents from the Bureau for Alcohol, Tobacco, Firearms and Explosives, the FBI and the Baltimore police raided the home of Katz's family in Baltimore 
Gunman 2017: "I'm one of the better players
Katz took the game name" Bread "to win Madden tournaments in 2017, said several players to CNN.
In February 2017 The Buffalo Bills Tweeted His Image He Won The Madden 17 Bills Championship. "Congratulations to David Katz, winner of the Madden 17 Bills Championship! Thanks for following Bill's fans, "was the tweet.
In an interview with former Buffalos Bills player Steve Tasker, Katz talked about his abilities.
" Personally, I think I'm one of those "He is a better player," he said.
CNN's Amanda Jackson, Dakin Andone, Sheena Jones, Evan Perez and Rosa Flores contributed to this report.