FORT DIX - Army Spec. William Richmond is getting an idea of what awaits him in Iraq when he begins a new military police mission, manning sometimes dangerous security checkpoints and guarding convoys.

But Richmond and other area residents in the New Jersey National Guard who trained here yesterday said they also face the unknown, the terrorist in civilian garb who turns a quiet moment into chaos and death.

"We're concerned about who the enemy is," said Richmond, 36, of Washington Township. "He could be anybody who walks around the corner. We don't know who they are."

Sgt. First Class Patrick Kildea, 43, of Aldan, Delaware County, said the "biggest concern is making sure you don't become complacent. Complacency kills."

Richmond, Kildea and about 180 members of the Guard's Third Battalion of the 112th Field Artillery are the "in-lieu-ofs," for lack of a better description. They will serve in lieu of military police, a precious resource in the Army now stretched thin by so many deployments around the world. They are expected to serve several months.

Yesterday, these provisional MPs received hands-on first aid instruction on how to save lives. Their patients were lifelike mannequins in camouflage uniforms and combat boots. Some had gaping wounds to approximate the effects of gunshots and explosives. Others exhibited the trauma of burns or head wounds.

"You assess the casualty and what injury has to be treated first," said Sgt. Eugenio Ortiz, 54, of Long Island, N.Y., who is in the fort's training support battalion. "They [troops] ask a lot of questions. We'll see how they do on the test."

Using the mannequins, along with volunteer patients from the 112th and a slide show, Ortiz taught a class of troops who sat at tables in full gear, including M-16s and other, more powerful weapons.

"Try not to cover the eyes or ears," Ortiz said as he dressed a mannequin's head wound. "They need to see what they're shooting at."

The troops learned how to treat shock, burns and all types of wounds, and how to stop bleeding and splint broken limbs. They had already qualified on their weapons at firing ranges and will take other classes to prepare for their mission.

Sgt. Kevin Kauffman, 34, of York, Pa., said the duty in Iraq "concerns me."

"You have to know where things don't seem right and get out of that situation," he said. "My job is to stay focused and bring all of us home in one piece." Kauffman, who is married and has a 3-year-old son, has been in the military 17 years. "I've always felt like I was on the practice squad. Now I can see if the practice paid off."

Pfc. Juan Delgado, 20, of Camden, volunteered to be one of the casualties and was treated for a head wound by Spec. Luis Ataca, 26, of Rahway, N.J. "Every soldier is concerned, but we have to do what we have to do," said Delgado, a student at Rowan University who is taking law and criminal justice courses. "We're pretty confident."

But soldier P.J. Lao, 23, of Ocean Township, conceded that the Iraq duty "scares me a little bit - the unknown, what's going to happen to us there. It goes through everybody's mind."

And although other soldiers had mixed feelings about their MP role, Glenn Erlenmeyer of Toms River, said, "I'm fine with it. If I didn't want to do it, I wouldn't have signed up." Erlenmeyer, 19, is getting married Feb. 8 at the Fort Dix Chapel and is awaiting the birth of a child.

Staff Sgt. John Betz, 35, of Sewell in Mantua Township, said his wife and 16-year-old son were "just waiting for me to come home." He probably won't head to Iraq until February or March.

"It's difficult for me not being around," he said. "But my wife reassures me everything will be fine."