ALEXANDRIA, Va. -- Just after 7 a.m. Wednesday, batting practice was wrapping up when the first shots rang out. A bystander's video captured the sound of bullets piercing the air.

Tennessee Congressman Chuck Fleischmann and others sprinted to the dugout where he says they felt like sitting ducks.

"Today I experienced the carnage of actual gun shots being fired first hand. It was horrific," Fleischmann said.

Witnesses say it soon became a gun battle between the shooter and police. Congressman Joe Barton, who manages the team, was there with his 10-year-old son, Jack, who took cover under a nearby SUV.

"Dozens if not hundreds of shots fired, it was scary," Rep. Barton said.

Congressman Rodney Davis was taking batting practice when the attack began.

"I heard a loud noise. I thought it was a construction site dropping a large piece of metal and then the next thing I heard was, 'Run, he's got a gun,'" Davis told CBS News.

Witnesses say the gunman approached a fence along the third-base line -- but never got on the field. Republican Whip Steve Scalise, standing on second base, was shot first. Other lawmakers took cover in the first-base dugout.

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Teammates say Scalise dragged himself across the field leaving a trail of blood. After the attack was over, Sen. Jeff Flake and others ran to his aid.

"He was just laying on the field. He had been shot in the hip," Flake said. "So we applied pressure and tried to stop the bleeding there."

Also shot: Zachary Barth, a staff member for Congressman Roger Williams and Matt Mika, who used to work on the Hill but now is a lobbyist for Tyson Foods. Two Capitol Police officers, Crystal Griner and David Bailey -- who are members of Scalise's security team -- were also wounded.

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Because of his leadership position, Scalise has a security detail with him at all times. Congressman Williams, who injured his ankle during the shooting, says without them, it could have been a massacre.

Rep. Roger Williams (R-Texas) speaks about the recent attack on the Republican Congressional Baseball Team in Alexandria, Virginia, during a news conference on Capitol Hill in Washington, D.C., on Wed., June 14, 2017. Reuters

"There could have easily been 25 or more deaths today," Williams said. "But officers Griner and Bailey prevented that and my family will be forever grateful."

Congressman Jeff Duncan left just before the shooting began. But he says he believes he encountered the gunman as he was leaving.

"I did have an interaction with someone in the parking lot who asked me if the team practicing was a Democrat or Republican team, I told him that they were Republicans. He said, 'K thanks' and turned around."

Hours after the attack, some members of the team still had their uniforms on. They were still trying to process what happened and how to move on.

"What we have to remember is this: that the American people ... excuse me," Fleischman said holding back tears, "... are great people."

"And we have great values. We represent great people every day," he said.

In all, four people were shot by the assailant. Scalise is in critical condition after surgery. Lobbyist Matt Mica is also in critical condition, shot in the chest. Griner, shot in the ankle, is in good condition, and Barth, shot in the leg, is also in good condition.

Members of the House have decided they will not give into fear. The game will be played as scheduled Thursday.