Transcript for The moment authorities breached Las Vegas shooter's hotel room: Part 4
second floor of mandalay bay and we're slowly working up. Reporter: The firing has stopped at this point, so it gives the swat team a time to take a breath and then begin to assess the situation because what they don't want to do is get anybody hurt. "Control zebra-20. We are at the end of the hall. We are gonna be peeking out into the hallway. Those officers that are down the hall need to acknowledge so we don't have a crossfire." Reporter: What police didn't know is that as they were trying to peek towards his suite at the very end of the hallway, he had full eyes on them. I need for everybody in the hallway to be aware and get back. We need to pop this and see if we get any type of response from this guy. To see if he's in here or if he's actually moved out somewhere else. We roughly have an hour, from the time that the security guard is shot, until the swat team makes an entry into Stephen's room. "Breach. Breach. Breach." So they use explosives that are particularly designed to blow doors. So it blows it back in the room, toward the bad guy. It creates such a blast that also allows law enforcement to immediately come in behind the blast. "We are clearing this room. We have one suspect down." "Is that room 135?" "That's affirmative. One suspect down in 135. I have the floor." He had killed himself. Now, he thought of everything, because he didn't use one of those rifles to kill himself, he used a handgun right in his mouth. Also in the room you could see the huge numbers of shell casings for all the rounds he fired. They found his weapons. "We've got the east room secure. One suspect down. Multiple firearms. This is definitely the place where they were fired into the crowd." I believe a vast majority were long guns. If you look at what pictures that have been released. So far, you see, I think, all the bump stock, which basically is a device when you place it on the gun, you can virtually put your finger on the trigger, and it literally will fire basically like an automatic weapon. Hey you guys! Get down! Go that way! Reporter: We wanna switch over to our Matt Gutman who is in Las Vegas at this very hour, Matt what do you know, what are you hearing? Reporter: What seems to be the pervading idea right now is that there's mass chaos, there is tremendous confusion, and really this is a city under a tremendous amount of fear, not knowing what's going on. I heard a medic scream that she needed help. She was tryin' to start a line on Natalia. I said, "What -- where's your wound?" And she said, "I have been shot in the back." I said, "If -- if you make it out there, I promise you I'll -- I'll make sure you're safe. And there was no ambulances out there. We had tactical people -- running out to our parking lot with their guns pulled. And they kept screamin', "Get down. Get down. Active shooter. There's another shooter. There's multiple shooters." Get out of here, there are gunshots coming from over there, go that way! They had like their armor and stuff and they kept telling us to go. And we just kept running across the street towards tropicana. There must have been about 1,000 people in the tropicana that I could see. I remember a staff came in and said the police have surrounded the building, we're on lockdown the safest place for you to be is right here on the casino floor. It's weird how your brain goes into hyper-focus mode. Everything went tunnel vision, but in a way where everything was clear and you can calculate every single decision you make. It just is tunnel vision at a certain point. You're paying attention to every single little thing. And yet, it's a twilight zone. It's just -- it's out of your body experience. Keep your head down and run this way! It was really scary thinking act if my sister is dead or if she -- I don't know where she is. So I said, "Natalia, we have to -- we have to take shelter behind this suburban, and I'll figure it out." So we hid behind the suburban. And I found a little lawn chair that was underneath it, and I put her in it. And we had a tactical guy come by us and say, "You guys have to get down," and I'm holding an I.V. Bag up. You guys okay? I need a rig, I need to get her transported. I was like can I please call my dad. So I called her dad on her phone. Gave her the phone. And she was so calm and said, you know, "Dad, I -- I've been shot. I'm gonna be okay. And I took the phone and I said, "Sir, I'm gonna take care of your daughter. I don't know how I'm gonna get her to the hospital, but we'll get there." Do you have any other wounded people to take? Not right now. Just go. Okay. Two men came and helped me carry sonny off the field into a truck. Those two men performed cpr on sonny the entire way to the hospital which seemed like an eternity and we ended up at a small hospital that was not a trauma center but we were the first people there. And I see the -- I see this Audi. Got the guy to come over, opened up his back door. And put Natalia in the back. She was getting numb. And I pulled out my phone. I was searching for pictures of my dog, and my wife, and my son, and she was just immediately lit up. It was so cute because his family is so beautiful. I love dogs. So he showed me his dog, white and fluffy. It was cool to see because this completely stranger is showing me his family. When we were rolling into the hospital I saw my sister in the wheelchair. And she was hooked up on the IV I believe and she was just like crying, there's blood all over her but I knew she was okay. We said we loved you, like loved each oer and held hands. We never really do that. So it was like different. Seemed like forever but must have been two, three minutes to get to the hospital. They were like he needs to go to trauma 1. It wasn't very long before I knew that he had passed. I mean, really in my heart I feel like it happened on the field. And they pronounced him. And I was right outside of the room when they did. And I just kissed him and hugged him. It's, like, W can this be real? How can I have come here to have a good time with my loved one, and leave without them? We got in the car and went the opposite way of the strip. Went over barricades, we ran every red light we could. And just kept going until we hit the desert. I just remember my brother coming to the door and I just hugged him so tight and we were both just crying. The first person I called was my son, and I said, "Sweetheart, there's been a mass shooting. And I'm in it right now." And I just told him, I said, "I love you so much. You're the best son in the world. And I'm so proud of you." I called my mom. And she was like, "Are you all right?" And I was like, "No. Like, mom, I've been shot." And they know me as a jokester, they thought I was playing and I was like mom, I'll send you a picture right now. She started balling tears. I really thought that was gonna be the last time that I would talk to anybody. I just remember the homicide detectives walking in to talk to me. And I just wanted to run away. Like, I don't wanna. You know, I don't wanna be the person you need to talk to. But I am. We heard about two fatalities and a number of people wounded. Once the press conferences started, basically in the middle of the night, and sheriff Lombardo began talking, the numbers started rising. It's cliche to say, but it was surreal. We determined there was a shooter on the 32nd floor of the mandalay bay. Officers responded to that location and engaged the suspect at that location. He is dead but we are interested in a companion that is traveling with him and her name is Marilou Danley. Okay. Marilou has disappeared. The big question is who is she, where is she, and what at this point does she know.
This transcript has been automatically generated and may not be 100% accurate.