After the first burst of gunfire, Erich Baumgartner dove for the floor, only to find himself looking up the barrel of his assailant's gun and watching as the stranger in the IBM building calmly reloaded.

"He was standing there pointing a gun down at me, and was pulling the trigger . . . it was clicking," Baumgartner recalled yesterday. As he watched the gunman reload in a "business-like way," Baumgartner jumped from the floor and began to wrestle for the weapon.

"I realized if I stayed around I would be dead," the 48-year-old Rockville resident said. But the gunman "was bigger than me" and during the tense scuffle Baumgartner suffered a broken nose and five cuts about the head. "I was losing this thing," he said, so he broke free and zig-zagged down a hallway to an office. He stayed there, the door locked, until police rescued him hours later.

Baumgartner lived to tell his version of Friday's bizarre events, which began when a man police identified as disgruntled former IBM employe Edward Thomas Mann rammed his car through the glass doors of the IBM building near Montgomery Mall.

When the siege ended, two persons lay dead--Hung Phi Nguyen, 40, of Silver Spring and Larry Lewis Thompson, 56, of Vienna.

Seven others were wounded by gunfire and two more people sustained injuries during the siege. Six people were still hospitalized yesterday, according to a Suburban Hospital spokesman: Richard Carl Kreutzberg, 44, of Chevy Chase, was in satisfactory condition with multiple gunshot wounds; Warren E. Winnie III 37, of Harper's Ferry. W. Va., in critical but stable condition with a bullet in the abdomen; Kenneth Tutwiler, 61, of Rockville, was in satisfactory condition after a heart attack suffered when he heard the shots; John O'Leary, 48, of Herndon, and Charles Dickerson, 27, of Silver Spring were in critical condition in the intensive care unit with multiple gunshot wounds. The most seriously injured was IBM security guard Jessie Roberts Lewis, 69, who was in critical condition after being shot in the neck.

Four others were treated and released: Doug Sontheimer, 40, of Silver Spring, was wounded in the left arm; John Francis McHale, 36, of Columbia, was wounded in the shoulder while hiding under a desk; Baumgartner was treated and released for the injuries he received during his scuffle; Pat Rollins, 28, of Gaithersburg, was treated for head lacerations and released.

Mann was arraigned at about 12:30 a.m. before a commissioner in Rockville, where he was charged with one count of murder and one count of assault with intent to murder. He is being held at the Montgomery County detention center pending a bond hearing Tuesday.

While some victims offered their personal perspectives, Montgomery County police yesterday continued inspecting the debris, interviewing victims and witnesses and trying to piece together the puzzle of Mann's life and his apparent rage.

A police spokesman said the gunman fired 150 shots during the 7 1/2-hour siege. Mann allegedly fired some of those rounds into a wall picture of a court scene, just before he surrendered, said police spokesman Philip B. Caswell. Police also said the gunman used at least two guns, one a handgun and one an automatic rifle, which he brandished when he first jumped from his car in the glass-strewn lobby and began spraying bullets at those in his path.

Police still withheld many details of the shootings yesterday, but some victims recounted their own experiences, and more than one said they were lucky to survive.

John McHale, one of the wounded, had expected "a slow day, the Friday before a holiday," when he heard the crash and the first sounds of gunfire.

"It was almost eerie," he said. "All I heard were the shots." McHale went to look out a window, then turned and saw the man with the rifle.

He dove under a desk from where he could see the gunman's feet approaching. "No one said anything, and you didn't hear anything before or after the shots," said McHale, who was hit in the shoulder when the gunman sprayed the office. He later left his hiding place and drove himself to the hospital.

Kenneth Tutwiler, 61, the heart attack victim, was in his office when the shooting erupted and could hear "moaning and groaning" in the hall outside, said his wife, Elsa. The commotion so frightened Tutwiler that he suffered a heart attack, she said. He stayed inside his office, behind a locked door, where police found him six hours later.