An undercover police officer who touched off the fatal shooting of an unarmed man outside a rowdy strip club after his bachelor party should be fired, lawyers for the police department argued Wednesday.

Detective Gescard Isnora's actions were not those of a calm, experienced member of the nation's largest police department, attorney Nancy Slater argued. Isnora, who dropped his cover by clipping his police shield on his coat, panicked and overreacted and ended up firing 11 times, causing the death of Sean Bell and the serious wounding of two of Bell's friends, Joseph Guzman and Trent Benefield, she said.

Isnora and Officer Michael Carey are being charged internally with wrongly firing their weapons. Carey, who fired three times, is facing the loss of 30 vacation days. The disciplinary proceeding follows a 2008 non-jury trial at which Isnora and two other officers were acquitted of criminal charges. Carey was never charged criminally.

Isnora said he believed Guzman had a gun because he heard him say "Get my gun" outside the club. He said he believed the men were going to their car to get a weapon and commit a drive-by shooting to get even with another group of guys with whom they had been arguing moments earlier outside the Queens club.

No weapon was found in Bell's car, sparking accusations that the NYPD was too quick to use deadly force in this case and others.

Attorneys for Carey and Isnora said the officers were doing their jobs in a stressful environment and shouldn't be blamed for a night gone awry, especially because the officers believed Guzman had a gun and because Bell hit Isnora with the car before pulling out and hitting a police van.

"If Sean Bell had only put his foot on the brake, we would not be here," Isnora's attorney Phil Karasyk said.

Slater, the police department attorney, said that because Isnora was an undercover officer, he had blended in and seemed to be just another bar patron, which confused Bell and his friends. Even though Isnora clipped his police shield on his coat, it was too dark to see, she said, and they could've thought he was a criminal.

She said Bell and his friends "had no reason to run from a police officer."

"They had no guns, and they had committed no crime," she said. "But clearly they had reason to run from a bad guy, from someone planning on robbing them or worse."

The police department also said that Carey wrongly fired only because he saw Isnora firing.

A department judge will review the case and make a recommendation. Police Commissioner Raymond Kelly makes the final decision.