In the event of an active shooter, the Advanced Law Enforcement Rapid Response Training Center says to avoid, deny and defend - in that order, if possible.
"He was just a guy".
What critics say: On the other side of the debate, gun control advocates argue that while silencers may help sportsmen, they also can help criminals.
Watson said he saw several injured people when he and his family ran from the scene of the attack.
Headline artist Jason Aldean was rocking the crowd at the sold out Route 91 Harvest Festival, while violence disrupted his set. The venue, run by MGM Resorts, stretches across 15 acres and has a capacity of 40,000 people.
Stephen Paddock lived in a community of senior citizens in the small town of Mesquite, north-east of Las Vegas.
However, the shotgun and rifle Paddock bought would not have been "capable of what we've seen and heard in the video without modification", Mr Famiglietti said. Only then can the nation decide whether these atrocities are the price we pay for being armed to the degree some people feel the need to be armed, or whether there are steps that should be taken.
But the debate since Las Vegas has centered on the piece of the bill known as the "Hearing Protection Act". If Paddock lost heavily and didn't file transaction reports, investigators still might be able to track his gambling fortunes by watching hours of casino videos that record every bet at gaming tables.
"One man had blood all over him and that's when I knew something was seriously wrong", Mike Thompson from London, told the BBC.
"If we had stayed in the front we would have been in the direct line of fire", Sorenson said. "Housekeepers are trained to respect guests' privacy, to not interfere with their items". Some investigators have suggested psychological issues, but there is no confirmation of this.
"The fact that [Paddock] had the type of weaponry and the amount of weaponry in that [hotel] room - it was pre-planned extensively", Clark County Sheriff Joie Lombardo said at a press conference.
"There is a long history of terrorists trying to elbow themselves into the limelight and milk some horrible tragedy to claim some credit for themselves", said Hoffman, who serves as Georgetown University's director of security studies. We have become emotionally and intellectually numb to this appalling toll.
Jessica Cabrera called her father from Las Vegas and screamed into the phone: "They're shooting at us".
He said when they "realised it was gunfire and everybody started running". "You could hear that the noise was coming from west of us, from Mandalay Bay".
The trip, which was supposed to last three days, was Harkins' first to Las Vegas.
Slowly, the names of the victims are surfacing.
Paddock was a frequent player "with the highest status" at Caesars Entertainment properties, a source familiar with the investigation told NBC News.
An off-duty Las Vegas police officer was another of those who died.
It became clear what was happening when the musicians left the stage.
President Donald Trump tweeted: "My warmest condolences and sympathies to the victims and families of the terrible Las Vegas shooting".
Sunday's shooting came more than four months after a suicide bombing at an Ariana Grande concert in Manchester, England, that killed 22 people.
Let's debate mass shootings and the broader scourge of gun violence as separate but related problems. Almost 90 people were killed by gunmen inspired by Islamic State at the Bataclan concert hall in Paris during a performance by Eagles of Death Metal in November 2015.
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