Transcript for Trump speaks in Arizona as state faces risk of becoming coronavirus hotspot
Now the health care heroes going wherever the virus takes them. Their latest battle ground, here's Matt Gutman. Today is my first day on the floor on my own. It's exciting, but it's a little bit scary. Reporter: Bridget Harrigan has answered the call of about, hospitals overwhelmed with covid-19 cases are desperate for help from people like her. Be putting me in the covid unit the whole time. So I'll want to be dressed up for that before I even get in the building. I was meant to go help on the front lines in some way. Reporter: The traveling nurse has seen what the coronavirus has done to a city. She has dedicated herself to fighting this pandemic starting in New York City. My hospital was full of patients, pull of people. I've been to hospitals before where the census was overflowing, but this was on a whole another level. Reporter: And as Arizona reaches its highest cases, she knew she was on to a new destination. In 21 states, hospitalizations are surging. And today the country's top infectious disease expert, Dr. Anthony Fauci warning congress it could get worse. Next couple weeks are going to be critical in our ability to address those surgings that we're seeing in Florida, in Texas, in Arizona and in other states. Arizona now a hot spot with over 58,000 cases and more than 1,000 deaths. Garrett Craig says he was the first covid patient to make it off a ventilator alive at this Arizona hospital. His 30-year-old son also infected with covid. I was still going out, wasn't worried about anything. I made it a joke, to be honest. Reporter: Father and son now warning others not to take this virus lightly. Social distancing is important. Wear a mask. It's a miracle that we're both here and we survived. Reporter: And the governor of Arizona encouraging cities to mandate masks to stop the I want to be clear. We recommend that all arizonans wear a face mask. Whenever you cannot socially distance. Reporter: And today, with thousands lining up to cheer president trump at this mega church in Phoenix, Dr. Sam darani who heads covid response for a hospital system here was shocked by what he saw. And all of this as his hospital system, he says, is seeing an alarming rise in hospitalizations just over the past 24 hours. You're talking about 10% increases per day. 10%, 20% increases in hospital admissions. Reporter: What does that mean for hospitals like yours? You're going to get to the point your you have overflow. Reporter: But the president's supporters dismissive. If a person doesn't feel like they need wear a mask I don't think they should be forced to wear a mask. Reporter: Are you putting people's lives at risk? No, I don't think so. I'm going to Arizona. It's a great place, great state. Reporter: In his swing throughout southwest, the president hoping to firm up support in the increasingly purple grand canyon state. First making a stop at the u.s.-mexico border, and just miles from where the president was, overwhelmed hospitals calling for every available nurse in the region and for volunteers from out of state. How short of nurses are you right now? We are having a situation where we don't have enough nursing staff. Reporter: From coast-to-coast, travel nurses descending on Arizona. We are here. Reporter: Deploying for duty on the state's front lines. Hospitals are starting to get filled up to capacity. Reporter: Houston based icu nurse Shannon Roberts flew to Phoenix for a six-week contract. I just go with no expectations. I just go in knowing that I'm going to have sick patients and knowing that I'm going to be there to take care of them. Reporter: Gina Mitchell drove cross country from Oklahoma to Arizona in her rv. Arizona! Reporter: Her boyfriend and two dogs along for the ride. You can call it a service, but this is my life. This is what I do. Reporter: This will be her first time working with covid patients, but she says her eight years as travel nurse have prepared her for the worst. I would rather somebody die with me sitting right there holding their hand, excuse me. I would rather hold their hand and get them through their journey than to have them die alone. Reporter: Bridget hair began knows first hand how bad it can get. She just wrapped up her last travel assignment in New York City. The epicenter of the pandemic, and she spent a month working in the icu of elmhurst hospital. When I got there, it was like a disaster zone. We treating it just like you learn as a nurse how you do disaster nursing and triage and everything. Reporter: By early March, the hospital in queens becoming ground zero, seeing as many as a dozen deaths in a 24-hour period from the virus. I've never experienced five to ten deaths in just a shift before. I've never experienced that gravity of the situation. It's physically taxing and emotionally taxing. This is my decontamination station as I like to call it. Reporter: Now wrapping up in her new role, hair began is doing everything in her power to keep herself and others safe. Seeing it in my opinion as bad as it can get and hearing that there's a possibility that somewhere else is headed that way was, that compelled me to come and help. We are reaching a point, we may not be able to take care of every patient to the best of our ability who comes into the hospital. Reporter: Dr. Jennifer ohea works at banner health in Phoenix. For months she's been in the trenches helping patients fight covid-19. She considers one thing critical to thwarting the virus. If I could ask everyone to do one thing stop the spread of covid-19 T would be to wear a cloth mask in public. Reporter: She joined a panel of doctors demanding that they make it easier for local leaders to mandates max wearing. I was so disappointed to see the lack of masking and social distancing that is so easy for the community to do in this public health crisis. Reporter: One of the state's biggest tests for whether arizonans are heeding the call to wear masks came in the form of that rally with president trump. Anybody worried about masks? No. Reporter: You're one of the few people I've actually seen out here wearing a mask. Well, I'm in the group of over 65. Reporter: Uh-huh. Or 65 or over, and I have asthma, and I'm disabled vietnam-era veteran, and I figured to be smart. Reporter: Do you have a mask? Did you bring a mask? I have one with me. Reporter: Are you going to wear one inside? No. Not unless required. Reporter: The mayor saying any elected official should set an example by wearing a mask, this includes the president. Dr. Derani, the covid response person was so alarmed he started snapping pictures. What percentage would you say are wearing a mask? About 1% to 5% probably. Reporter: In a city going through its surge right now, what does it mean? It's not good. Any mass gathering is going to propagate the spread ever covid-19. Here we are on our way to see president trump. Reporter: Nadia Larson was determined to see the president, waking up at 5:00 A.M. To be one of the first at the rally with her friend and fellow trump supporter. Though she's considered in the high-risk category as a breast cancer survivor, she is not planning to wear a mask. I fight any viruses with my supplements, the vitamins I take, all five of them. I take my CBD, destress and stay in the sun every day ten minutes to kill the virus. My immune system is strong, and if I get the virus I get over it. Reporter: Tonight she cheered on the president, both of them not wearing a mask. We're doing so well after the plague. It's going away. Reporter: And as Bridget Harrigan comes off her shift, she says she's hopeful that the crisis that she saw in New York won't become reality in Arizona. But she is ready. I've been there for one shift in the hospital, and it's not as bad as New York, but it could, it has every capability of getting there if the cases rise and it overruns the hospital, so I'm hoping that that doesn't happen while I'm here, but if it is, that's what I'm here for. Reporter: For "Nightline," Matt Gutman in Phoenix, Arizona.
This transcript has been automatically generated and may not be 100% accurate.