When human rights crises and natural disasters break out around the world, some people are tasked with running into the very places that the majority of people are running from. Aid workers, doctors, nurses and other emergency personnel must be ready to respond quickly. But among those humanitarians, there is an even smaller group charged with being the first ones in to some of the toughest places on Earth.Emily David is part of the International Rescue Committee's Emergency Response Team , a group of about 40 people whose job it is to figure out how the aid agency will respond to a given crisis, and to figure it out fast. For David, that means being ready to hop on a plane within hours of learning where her next destination will be."You will get a phone call, or an email, and you will need to be deployed within 48 hours. And they will literally say, 'A situation has occurred, we're sending in an initial team to do an assessment and set up the programming,'" David told Refinery29. "You don’t have an office there. You check into a hotel, or whatever accommodation you can find. And then you hit the pavement."It's a job that means long hours, uncertainty, and often putting family and friends on the back burner. But the 43-year-old Australia native loves it. Bringing relief to the world's most vulnerable people — refugees, migrants, those who have lost their homes in floods or fires — is tough, but also rewarding work, David said.Ahead, David shares her story and photos of her work from Serbia, where she has been on the ground helping people during the worst refugee crises since World War II. Editor's note: This interview has been edited for clarity and length.