DENVER (AP) _ Richard Nichols was running late. His wife was waiting in the lobby of the Regency Towers near the Oklahoma City federal building so they could take their nephew, waiting alone in the car, to a doctor's appointment.

Jurors in the trial of Timothy McVeigh viewed black-and-white surveillance pictures of the lobby as Nichols met his wife and walked out the doors at 20 seconds after 9 a.m., the final frame the camera took that day.

``I took about two steps when there was a terrific explosion,'' the maintenance worker testified Wednesday. ``We felt heat and pressure and it kind of spun us around a little bit.

``I grabbed her and she yelled out, `What's going on?' I thought the boilers blowed up. ... We made a lunge for the car because my little nephew _ he was in the car.''

A block away, the federal building was blown apart by a bomb hidden in a Ryder truck _ the same truck the Regency Towers security camera caught driving by minutes earlier. The glare obscured the driver's face.

Had Nichols left his job at the Regency apartment building on time, he, his wife and nephew would have been driving past the Murrah building when the blast ripped it apart, he said.

Instead, the couple were caught in a maelstrom of smoke, glass and chunks of cars and buildings as they tried frantically to unstrap the seat belt of their 10-year-old nephew.

``I seen this humongous object coming to us out the air. And it was spinning like a boomerang. And you could hear this `woo-woo-woo-woo' noise. And I looked and I seen it; and I told her _ I said, `Get down.'''

The Ryder truck axle smashed into the Ford Festiva's windshield, snapping the rear end of the compact in the air and driving it 10 feet backward with his wife, Bertha, and nephew, Chad, inside.

Nichols raced after the car.

``I grabbed my wife, and I grabbed Chad, and I kind of hovered over them like an old mother hen and took off across the street with them,'' he said.

They were OK, although Chad had the beginnings of a lump on his forehead.

Curtains fluttered out the blown-out windows of the 24-story Regency Towers. Nichols saw a scaffold up high along the building and yelled to the men on it. They waved and climbed in through a window.

Then he looked around.

``It was just like there was a, like a brief pause in the smoke and just everything just kind of separated; and you could see that the whole front of the Murrah federal building was completely demolished,'' he said.

As Nichols testified, one of the jurors buried her face in her hands for several minutes. Later, she rubbed an eye.

The 7-foot-long, 250-pound axle has turned into a key piece of evidence in the trial of McVeigh, who faces the death penalty if convicted in the April 15, 1995, bombing _ the deadliest act of terrorism on U.S. soil.

Vehicle numbers from the part were traced to a truck belonging to a Kansas rental office. A worker there claims it was rented to McVeigh under another name two days before the explosion killed 168 people and injured 500 more.

An expert was expected to testify today that other burned truck parts found at the scene also could have come from the Ryder truck.

Prosecutors contend McVeigh, a 29-year-old Gulf War veteran, was an anti-government sympathizer who wanted to retaliate for the FBI's deadly 1993 raid on the Branch Davidians near Waco, Texas. He wrongly believed the orders for the raid were given by federal agents at the Murrah building, they say.

Eight federal law enforcement officers died in the Oklahoma City bombing.

Former Secret Service agent Lawrence Kingry was across the street in the federal courthouse when the bomb hit. When he ran out into the street, he could tell that his agency's ninth-floor offices _ and his coworkers _ were gone.

``I could see completely through the building,'' Kingry testified. ``I didn't go up to the ninth floor because I knew our people were dead.''