As the investigation into the events surrounding Las Vegas terrorist Stephen Paddock's attack on Route 91 Harvest festival continues, Mandalay Bay Resort and Casino security guard Jesus Campos is speaking publicly for the first (and only) time. Campos and Mandalay Bay Resort and Casino building engineer Stephen Schuck discussed the moments leading up to Paddock's attack in an interview with Ellen DeGeneres set to air Wednesday.

"I'm doing better each day, slowly but surely," Campos told DeGeneres. "Just healing, physically and mentally." Campos and Schuck then walked DeGeneres and the audience through what they saw Oct. 1, just before Paddock—a terrorist—opened fire on the music festival crowd and killed 58 people. Campos said he was walking from the 31st to the 32nd floor of the property when he noticed a door was blocked. He later discovered the door was blocked by a "metal bracket," at which point he notified security officials and requested engineering assistance.

Then, Campos said, he heard "drilling sounds" nearby. When a nearby door slammed, shots started ringing out into the hallway through the door of Paddock's room. "At first I took cover," Campos said. "I felt a burning sensation. I went to go lift my pant leg up and I saw the blood. That's when I called it in on my radio that shots have been fired. I was going to say I was hit, but I got over on my cell phone just to clear that radio traffic [so] they could coordinate the rest of the call."

When Schuck made it to the 32nd floor, he discovered Campos and heard what he initially thought was the sound of a jackhammer. "That's when Jesus, he leaned out, and he said 'Take cover! Take cover!' and yelled at me, and within milliseconds, if he didn't say that, I would have got hit," Schuck said. "It wasn't even fully in cover. [Shots] were passing behind my head. I could feel the pressure." At one point, another property guest entered the hallway but was quickly instructed to take cover in her room.

DeGeneres added that both Campos and Schuck had declined her show's offer to be paid for their appearance. She also announced that Shutterfly would be donating $25,000 to the Las Vegas Victims Fund.