SIOUX CITY | Tom Benzoni is in the midst of a "mid-life crisis."

The Sioux City physician, dressed in green scrubs, explains he's happy, as he sits in a dimly lit family waiting room just off Mercy Medical Center's emergency room. 

His car runs. His youngest child is a senior in college. He's comfortable financially. Yet inside the 58-year-old feels a gnawing sense that it's time for a major life change.

He'll soon leave Mercy Medical Center's Emergency Room, where he's tended to heart attacks, traumatic injuries from car crashes and shotgun wounds for 20 years, and take his life-saving skills around the globe.

"I still love what I do. It's just a riot. ... How will I do without all of this stuff -- without air-conditioning, without CAT scans?" Benzoni says, gesturing widely. "Is it the stuff or is it me? We'll find out."

Benzoni answers his cellphone and requests an EKG for a patient while discussing his future plans. He was instrumental in making Mercy the catch basin for trauma cases in Northeast Nebraska and Southeast South Dakota.

The first stop on his itinerary: Haiti. The poorest nation in the Americas is still recovering from an earthquake that devastated it more than four years ago. He'll travel there with a delegation from the University of Iowa in January to train local doctors and then join CNOS orthopaedic surgeon Steve Meyer's Siouxland Tanzania Education Medical Ministries, STEMM, on a March trip to the East African country of Tanzania.

The STEMM team performs surgeries, offers medical treatment and provides education training at Selian Lutheran Hospital in the city of Arusha. STEMM also maintains an orphanage nearby.

If Benzoni can handle the challenge, he plans to join Doctors Without Borders (Médecins Sans Frontières) next year, a long-term goal of his. The French-founded humanitarian aid organization provides health care and medical training in developing and war-torn countries and regions facing deadly disease outbreaks.

His trauma experience, his training in underground search and rescue and the four years he and his wife, Noreen O'Shea, spent practicing in Appalachian Kentucky with the National Health Service Corps, Benzoni believes, have prepared him for the work.

"I felt like I made a difference there," he says of Kentucky. "But I also felt that those were people who were incredibly warm and welcoming. They had nothing and they shared the nothing that they had."

Benzoni applied to Doctors Without Borders hoping to join an immediate dispatch team that responds to disease hot spots. After an interview in New York City, he was invited to attend a training session in Denver, Colo., which tested his problem-solving, communication and leadership abilities. He says he was the oldest guy there. All of the other doctors were in their 30s.

Benzoni, a marathon runner, says he's up for the challenge of living in an austere environment and believes he would cope better than someone half his age.

"The next person down, I could've been their father," he says. "Basically their response was, 'We want to see you do some field work someplace before we'll let you do that kind of work.'"

Benzoni is fascinated by the work the organization is doing to contain an Ebola outbreak ravaging West Africa. The viral illness that kills 60 to 90 percent of the people it infects has claimed nearly 700 lives since the current outbreak began in February.

The onset of flu-like symptoms (fever, weakness and muscle pain) are followed by vomiting and diarrhea. The kidneys and liver begin to fail. Some patients develop internal and external bleeding before succumbing to the illness. The virus, which has been linked to fruit bats, spreads through contact with the blood, organs and bodily fluids of infected people and wild animals.

"They've set up an Ebola hospital that has a 6-foot ring that nobody's allowed to cross in their clothes -- even to the extent that the doctors taking care of the patients come to the edge of the inner ring, give them the patient number and then they read off the vital signs of the person," Benzoni explains. "They don't even bring the paper from the inner section to the outer section. That kind of thought pattern, I really like."

The lack of predictability in such an environment, Benzoni says, could be very difficult for some.

"Don't pull my fingernails out and give me something to eat and I'm good."