Last week, there was a practice exercise in a city that's already had more than its share of practice. A dozen and a half young men and women lay on the hot asphalt of Jerusalem's Teddy Stadium parking lot. In real life, these actors are sixth-year medical students, soon to be the next generation of Israeli doctors. They've just finished a special course in terror medicine, an innovation added to the Israeli curriculum.

A lot of effort has been invested in making the scene look gruesome. A professional make-up team has splattered blood on the make-believe victims' limbs, faces, and torn clothing. One has a nail "stuck" to his chest. A leg is pitted with pretend holes. Many others have ugly burns. The sun beats down, and genuine sweat mixes with the special effects.

The action starts with the boom of an explosion and ocher smoke rising. Sirens wail from a police car parked catty-cornered. Several of the students lie still; others are writhing and moaning. On the sidewalk, a student lets out a blood-curdling scream. Torn plastic limbs, a mangled boot, a twisted face mask, tattered manikins are scattered on the ground, like in a Foreign Ministry video. The bottom half of a body in army trousers is the dead terrorist.

Other students in red T-shirts marked "doctor" run forward to treat the make-believe patients. A genuine trauma surgeon, Dr. Avi Rivkind, walks briskly with a microphone, urging his proteges to work faster. Every second counts. A pretend bystander is screeching. She throws herself on a "pregnant" patient, wailing that the unborn baby must be saved. A real Magen David ambulance pulls up. A portly Hassid searches for body parts and scoops up a macerated baby-sized doll. A real photographer takes pictures. A woman with long auburn hair quietly walks forward. She's wearing a backpack.

"Another terrorist!" someone shouts, and in seconds she's face down on the asphalt with real Jerusalem police tackling her and removing pretend explosives. She wriggles and writhes. "Hold down her legs," a policeman orders. Jerusalem Police

Chief Mickey Levy once told me about a terrorist wriggling on the ground in northern Jerusalem, trying to set off the explosion after he was apprehended. Giving the order to shoot him was one of Levy's hardest directives.

Suddenly, men in white and yellow suits, wearing gas masks and wielding submachine guns, run by with stretchers. They're police officers - or students playing police; by now I can't tell. The police have added a biological and chemical threat element as a surprise, their own macabre twist to the imaginary scenario of a terror attack at a soccer game. Levy is there scrutinizing.

"Is what we see here behind us or ahead of us?" I ask. "Ahead of us," he says, without missing a beat. Gas and biological, too? He shakes his head no. "I hope not."

The newly rising Center for Emergency Medicine at Hadassah Ein Kerem is equipped for the staff to work inside for two weeks in case of a gas attack outside. He raises his eyebrows. "I didn't know."

Rivkind demands that two students evaluate a "patient."

"No pulse. No breathing," says the soon-to-be-doctor. "And the third sign? Look in the eyes!"

"Dead," the students say tentatively.

"Then why," asks Rivkind, "are you still treating him? Move on to the living."

At last, the evacuation begins. The "doctor in charge" reels off the summary of head injuries, abdominal injuries, burns, and dead.

I see a young neighbor, part of the make-up team. Just last month, I was her volunteer "mature" model for a class in party make-up. She spent that evening putting on and taking off eye shadow. Her teacher has summoned her for this unique Jerusalem assignment. "The worst was creating the fractured jaw," she says.

Leaving, I hear the real news on the radio.

Soldiers have been seeking out terrorists in the crowded streets of Gaza. A terror cell is uncovered in Jericho. Recent security reports say the security fence will make it difficult for terrorists to reach other areas, so Jerusalem is even more likely to be the site of future attacks.

This year, 65 percent of the total fatalities inside Israel have been in Jerusalem. The last news item is a public announcement that the activity at Teddy Stadium is only an exercise.

Two years ago, for the sake of realism, an Arab medical student volunteered to play the terrorist. But as the exercise got underway, he was terrified that an armed bystander who didn't realize this was an exercise would shoot him.

Today, one of the medical students tells Rivkind that he can't take the pressure and will choose a quiet specialty.

But Rivkind believes that no matter if you're a skin doctor or a radiologist, you might find yourself in a mall, near a bus, in a cafe when terrorism strikes. Practice helps with medical skills and the emotional equanimity. But don't confuse knowing what to do with getting used to it, he says.

You never, never get used to it. Never. Nor should you.