There's an elite group of soldiers on Fort Hood who are in the business of saving lives.

Now hundreds more are vying to join their ranks, but not everyone will make the cut.

Sergeant Gordon Perkes dives behind sandbags, fighting against simulated artillery, then disables a trip wire that triggers a mock grenade.

He's fighting to get to a vehicle full of would-be wounded comrades who need his help.

The task is one of dozens of tests and physical challenges he must overcome to receive the Army's elite Expert Field Medical Badge.

"It's been a couple of stressful days, a lot of different things, like land navigation today, we're going to crawl through the mud a little bit," Perkes said.

The strenuous and demanding, ten-day event began a week ago with about 380 candidates, each with their sights set on donning the prestigious mark of achievement.

Private First Class Alex McAdam says, "It means you can follow directions, and do what you're told, and be able to operate well under stress."

As of this Monday, only about 130 candidates remain, and one missed step can send them home empty-handed.

"These are life-threatening casualties that we have here, the events themselves, so the tasks, if they're missed, could lead to death," said Captain Daniel Davis, with the 1st Medical Brigade.

Throughout the event, the candidates are actually sleeping and living out in the field, learning to maintain that level of difficulty and stress they would encounter in a real life combat situation.

"We want to give as much simulation to the real world scenario as possible," said Captain Davis.

The event ends Friday with a 12-mile foot march that must be completed in just three hours.

Deployments caused the frequency of Expert Field Medical Badge events to decrease for about a decade.

They've been regaining momentum since about 2010.

Reporter: Sophia Stamas

Photographer: Chris Buford