Las Vegas police have released the terrifying bodycam footage from first responders to the scene, where 59 people were shot dead on Sunday evening.
Another 500 were injured at the country music concert in the deadliest gun massacre in modern American history.
- As it happened: Several shot at country concert in Las Vegas
- A glimpse at the United States' shocking mass shooting stats
The footage shows an officer crouching behind a wall, frantically instructing the public to get down and away, while trying to figure out where the gunshots are coming from.
Unknown to them, retiree Stephen Paddock was shooting from a hotel room above, armed with 23 weapons and thousands of rounds of ammunition.
The policemen all stay down next to a patrol vehicle on Las Vegas Boulevard, when one of the officers is shot.
The video then moves to another officer, who stands over a woman, as the bullets rain down.
"I have a vest on," he assures her.
He then makes a run towards the concert to try and help those at the scene, where the video ends.
"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. "I'm pretty sure he evaluated everything that he did in his actions."
Cameras have now been discovered in both the room and the hallway, with police believing they may have been used to watch for people approaching him.
- Las Vegas shooter: Inside the killer's room
- Las Vegas gunman Stephen Paddock may have planned attack on Lorde concert
The motive behind the retired man's actions is still being investigated, but police say he acted alone, despite ISIS claiming responsibility.
All but three of the victims have been identified, but police say the death toll could still rise.