Two people flew by the stairwell door, sprinting away from the action.

It was a man and woman in American business dress.

Mahoney didn’t hesitate. He was out after them. And I was right behind.

The couple raced down a long row of parked cars toward the circular ramp at the far end of the garage. The woman had a pistol in her hand and fired blindly back over her shoulder as they went. Even firing like that, she was accurate, skilled.

We took cover behind the nearest parked car, an Audi A6. A bullet ricocheted off the hood and took a divot of shiny silver paint and metal with it. Too close.

Gunfights are never fair game for the police. The bad guys have no rules whatsoever. We have to know exactly what we’re shooting at and what’s beyond it. The best strategy is to stay as unpredictable as possible.

I kept to a low crouch and ducked around the back of the car. Once I reached the far end, I popped up, squared my feet, and got off one fast shot before they even knew I was there.

My vision tunneled around them like a spotlight. There was a flash of red.

I’d caught the man in the right hand. He yelped, but they didn’t slow down. The woman returned fire, pushing him ahead of her now. She was very good with a gun.

They cut between two cars and scrambled over a concrete barrier. A second later, they’d dropped down to the level below and disappeared.

Already, Ned Mahoney and I were up and running again.

“Careful, Ned, she can shoot lights-out.”

I THREW MYSELF over the parking barrier after our two runners and jumped maybe ten feet. The cement landing was a vicious jolt to the bones. I had to drop and roll before I got up again, just to save my legs.

There were several dime-size red blotches on the ground where I landed, but nothing to indicate which way they’d gone. The guy might have wrapped his hand.

All I could see from here were lots of parked cars, concrete, and a dozen ways out.

“What the hell?” Mahoney came running up behind me. Several more SWAT officers were sprinting down from the level above as well. “Where’d they go?”

“Any sign of them?” Command radioed down.

“Negative,” I said. “Get all the exits covered. And shut down the block if it’s not too late.”

We all fanned out, checking the adjacent rooftops, throwing open doors, looking under cars with any kind of clearance. But it was no good. They were gone. Somehow, they’d gotten past us. The woman was a professional. She didn’t panic and she could really handle a gun.

There was still a chance someone could pick them up on the street. Their faces were a matter of record now, and every unit in the city would go into high alert.