Jesus Campos, the Mandalay Bay security guard who alerted police to the Las Vegas shooter, is speaking out for the first time about the violent encounter that left him with gunshot wounds.
Jesus opened up to Ellen DeGeneres ... detailing the harrowing moments leading up to him discovering Stephen Paddock on the 32nd floor, just as he was starting to open fire on the crowd of concertgoers below.
He thinks a loud slamming door during his routine check of the floor is what tipped off his location to Paddock, who then started shooting into the hallway -- and hit Campos in the leg.
Miraculously, Campos says he was still able to somehow get on his radio and tell his team shots had been fired. You can hear his full story on Wednesday's episode of 'Ellen.'