In its broad outlines, we know this story: mass shooting, dozens dead, more injured.

But authorities are still trying to piece together exactly what happened at Pulse nightclub in Orlando, Fla., nearly a week ago, in what is the deadliest mass shooting in modern U.S. history.

The chaos unfolded quickly inside the nightclub late Saturday night, where Omar Mateen gunned down 49 people and injured more than 50 others.

"We just went from having the time of our lives to the worst night of our lives, all within a matter of minutes," says Patience Carter, a 20-year-old from Philadelphia who was visiting Pulse — and Florida — for the first time.

The gunman was bursting in and out of the bathroom, making calls to 911, shooting more people — as police were sneaking into the club to get victims out and trying to figure out how to overtake the shooter.

In the surrounding neighborhood, residents watched helplessly at a scene that looked like something out of a movie.

Bobby Edge, 58, lives across the street from Pulse. His barking dog woke him up. It was 2 a.m.

"All of a sudden you started seeing people everywhere," Edge says. "And they started running into this parking lot. And people started going, 'Where is such-and-such? Where is such-and such? I've been hit, I've been shot, such-and-such is dead.' "

And at the Orlando Regional Medical Center — about half a mile from Pulse — emergency room doctors describe how the patients starting coming in: one, then another, then another, by ambulance, by the truckloads.

"The flow did not stop, and I quickly realized that I needed to call backup," says Dr. Chadwick Smith. "I said, 'Please come. Please come. We need your help.' "

As the police closed in on the shooter, he used his final moments to inflict more pain on his hostages.

"He said, 'Hey you' to someone on the floor inside the bathroom. And shot them. Shot another person and then shot another person who happened to be directly behind me," says Patience Carter, who was in the bathroom with the shooter.

As the sun rose over Orlando on Sunday morning, Francisco Pabon was outside Pulse, frantically trying to find the friends he had been with inside the club. He waited in the streets for hours. In all, seven of his friends died. He got word about the final death at 9:30 a.m.

"She told me, 'He didn't make it.' We burst into the tears. I was asking, 'Why?' They were hours of despair and anguish," Pabon says.

These men and women are among the dozen or so people NPR spoke with, using their voices and experiences to reconstruct the events of that deadly night.

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