Orlando, Florida - A man who was in an Orlando office when a former employee came in and started shooting said Monday that the ordeal that left one dead and five injured lasted about a minute.

Mark Davidson, a vice president at the engineering firm Reynolds, Smith and Hills, said Monday that his co-workers stayed calm Friday and didn't scream as Jason Rodriguez entered a reception area of the eighth-floor office and began shooting randomly.

"Nobody was screaming or yelling," Davidson said. "It wasn't panicky."

The gunman pulled a pistol from a holster under his shirt in the reception area of the U-shaped office and began shooting. At first, Davidson said he didn't know what the noise was. He thought it might be balloons popping or book shelves falling over. There is only one main entrance to the office from outside, and it was typically unlocked during business hours.

The building had security guards posted at a desk on the first floor, but visitors could come and go with relative ease before Friday's shooting.

The noises kept getting closer and Davidson saw other people running, and he knew something was wrong.

Davidson ran to back of the office where other workers had gathered and they waited a moment, trying to piece together what was happening. They then saw the gunman from about 25 yards away as he had made his way about three-quarters through the U-shaped office. They fled.

"You're seeing the shooter and you put two and two together," Davidson said. "You knew we were, as a company, victims of a senseless crime."

Rodriguez has been charged with first-degree murder, and Orlando Police Chief Val Demings said Monday that more charges are expected. The shooting caused havoc in downtown Orlando as authorities scrambled to find Rodriguez, who was eventually tracked to his mother's home. He surrendered peacefully, but later remarked to reporters that he went on the rampage because his former co-workers "left me to rot."

An attorney for Rodriguez has portrayed the 40-year-old as a mentally ill man who fell victim to countless personal and financial problems. Rodriguez left his engineering job at the firm two years ago and hadn't been able to find comparable employment since then. He most recently made less than $30,000 a year at a Subway sandwich shop.

"There were performance issues over time and there had been reviews we had with Mr. Rodriguez trying to correct the situation and trying to direct him to another level," said Lerrie Jenkins, chairman and CEO of the firm. "It just didn't work out so we agreed mutually for him to leave the company and he signed a letter of resignation."

After his arrest Friday, Rodriguez told detectives that he blamed the firm for hindering his efforts to get unemployment benefits. Company officials were perplexed at that explanation given that he had worked elsewhere since leaving the firm.

"We worked with Mr. Rodriguez so that he was allowed the opportunity to voluntarily resign and be eligible for unemployment income," said Jim Avitabile, a vice president at the firm. "This was not an abrupt termination."

Otis Beckford, 26, was the lone fatality in the shooting. One of the shooting victims, Ferrell Hickson, was released from the hospital late Sunday. The other four victims remained hospitalized in stable condition.