Army 2nd Lt. Michael Polmear had just decided to call it a day amid wet conditions on a climb in Wyoming's Grand Tetons in July when light dust and gravel began to shower down from above.

Polmear, an experienced rock climber, recognized the warning signs of an impending rockslide and hustled to move out of the way.

And he may have succeeded — if not for a mammoth 500-pound boulder that broke loose and came crashing down to shatter his left arm.

"It was a big rock, about two cubic feet," said Polmear, who was 100 feet up the challenging Dike route on Middle Teton at the time.

"Oh, yeah, I screamed."

At first, Polmear didn't see a lot of blood. But moving his arm and loosening his sleeve released a "deluge," as he described it.

His upper arm appeared flattened, with bone and pulp oozing from an 8-inch gash. Picture a rolling pin's effect on a jelly donut.

Fortunately for the 27-year-old soldier, he had just wrapped up his first year of medical school at the Uniformed Services University of the Health Sciences, in Bethesda, Maryland.

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One year of training may not seem like a lot, but according to Polmear and the USUHS faculty, the school's first-year requirements, including military hands-on field training, likely saved not only his career, but his life.

For Polmear, his training kicked in from the moment he realized the severity of his situation. Facing a sheer rock cliff and a dangling, useless arm, he assessed his situation from the perspective of his USUHS Combat Medical Skills Course.

To wit: Bone protruded from his arm; the gushing blood was dark, indicating it was venous and not arterial; his hand was limp and numb but still pink.

"I knew at that point that I probably wouldn't die right there, so it gave me some time to plan my next moves," he said in a recent interview with Military Times at USUHS.

He contacted his climbing partner and wife Stephanie via radio to check on her status and tell her he'd been hit. He then proceeded to stabilize his arm and set an anchor so Stephanie could lower him to the ground.

Once down, he performed a more advanced assessment of his condition, checking his pulse, cleaning the wound with water and pushing the bone fragments back into the gaping gash for possible later use in surgery. He also made a temporary tourniquet, which he later replaced with a combat application tourniquet that he always carries in his backpack.

Meanwhile, Stephanie had been trying to call for a rescue, but cell phone service was limited. Fortunately, other nearby climbers heard the rockfall and Polmear's shouts and rushed to the scene — and their phones worked.

"Here's to Verizon!" Polmear said.

The group placed a call to the dispatchers for the Jenny Lake Rangers, one of the Teton's top mountain rescue organizations, and were notified that the park rangers had just received a call for another rescue. But once Polmear told them he probably needed surgery within six hours — he was "urgent surgical," as he had learned at USUHS — he went to the top of the list.

Jenny Lake Search and Rescue sent a helicopter, along with a team trained in tactical combat casualty care techniques by Dr. Will Smith, medical director for Grand Teton National Park and an Army reserve lieutenant colonel.

"I couldn't believe it — they asked me if I needed pain medication and they had ketamine — they even use the same dosage measures we do in the military," Polmear said.

The med school student then was transported to St. John's Medical Center in Jackson, where, despite arriving in a place flush with full-fledged doctors, he continued to advocate for his own care. He asked specifically for a surgeon versed in upper-extremity repair and nerve reconstruction in the hope that his arm and hand could be salvaged.

And he didn't listen to the doctors who were trying to prepare him for the worst-case scenario: amputation.

"The doctors said, 'Worst-case scenario, Walter Reed has great prosthetics,' " to which I responded, 'Yes, but they have a better rehab program,' " Polmear told a USUHS press officer after the accident.

His surgery took seven hours and involved three different specialists. Then came a long recovery, which Polmear oversaw every step of the way in an effort not only to preserve his hand and arm, but to give him a shot at continuing his career plan, which, from day one at USUSHS, was to become a hand surgeon.

"The irony of this injury has not escaped me," he said.

In the hospital, Polmear tapered himself from pain medications so he could feel sensation and pain in his arm and recognize any early signs of compartment syndrome, a condition that often occurs after a crush injury or battlefield trauma that causes muscles to swell and constricts blood flow.

He began moving his arm and left the splint off to speed recovery. And after more than two weeks in Jackson, he returned to Bethesda, Maryland, for a summer rotation in disaster and humanitarian assistance medicine as well as additional rehabilitation and surgery at Walter Reed National Military Medical Center.

Less than 10 weeks out of surgery, Polmear is now into his second year at USUHS, attending classes and going to occupational therapy at Walter Reed-Bethesda, and is back to running 40 to 50 miles a week.

Navy Capt. Patricia McKay, an orthopedic hand and upper extremity surgeon who serves as assistant dean for clinical sciences at USUHS, said Polmear's calmness and quick thinking in his crisis gave him the upper hand in continuing his plans to become a surgeon.

"His positive attitude and early intervention undoubtedly made a tremendous difference," McKay said. "I have met surgeons with far greater physical limitations and they are very good. He will have to adapt to the diminished strength and coordination in that hand, but it is manageable."

USUHS officials can recall several instances when students have used their training to save lives, including a 2013 accident in which two students saved a man's life in Gaithersburg, Maryland, after a car had crashed into a Sam's Club and struck him, severing his leg.

But they can't remember any other examples of students using their training to save themselves.

McKay said the USUHS students who saved the Maryland man credit the same course that Polmear claims gave him the knowledge he needed to react to his own situation. She also praised Polmear's wife Stephanie for her ability to stay calm in an intense situation.

"If she had panicked, there could have been two individuals to rescue," McKay said.

Polmear said the experience will make him a better doctor, with an improved understanding of the patient experience.

McKay agreed. "He will be able to draw on this experience to enhance his interactions with patients and the medical staff. He is a great example of the common Marine Corps slogan, 'improvise, adapt, overcome,' " she said.

Polmear said he eventually wants to return to rock-climbing, but for now, he and his wife, both experienced climbers who began dating over the sport, are keeping their feet on the ground.

When they do return, though, Polmear said he'll be ready for any medical contingency.

"The combat medical skills that are woven through our curriculum are very helpful. Mostly because they kept me calm. It would have been a lot more complicated if I had freaked out," he said.