When six lanes of police cars 20 deep, a SWAT team, FBI and at least three overhead surveillance helicopters and aircraft responded almost immediately Thursday to a 911 call of a suspected shooter at the Washington Navy Yard, the reaction was a direct reflection of years of hard lessons learned from the 2013 massacre that left 12 dead.

Thursday's report was ultimately a false alarm after an employee reported what he or she thought were gunshots. The area is under a large amount of construction and even as the emergency response unfolded, area cranes and drills were still pounding away, adding to the confusion.

The response and interoperability of agencies was far different than in 2013, when law enforcement and the Navy Yard were criticized for inconsistent communications and delays in response.

A myriad of reviews into D.C.'s emergency response followed the fatal 2013 events. Washington D.C.'s metropolitan police department did an in-depth after action report; the Pentagon assigned now Defense Secretary Ash Carter to lead two internal reviews — one on the physical security at Defense Department installations, and the other on the security clearance process. Multiple congressional hearings were held and both the Pentagon inspector general and the Government Accountability Office weighed in on the issue.

On Thursday, several of those lessons learned were on display. One of the key takeaways of the 2013 shooting was that the Navy Yard's internal emergency communications system was not relaying information to the city's police and fire services. The Navy Yard's emergency response is initially provided by either Defense Department or contracted security, and in 2013, the radios lacked interoperability with local services.

On Thursday, a far different response occurred, D.C. Police Chief Cathy Lanier said.

The call was initially placed by an employee of Naval Sea Systems Command at 7:29 a.m. and went to the base's emergency call center. Once the nature of the call was identified, "it was then immediately taken by the Naval District of Washington police, and broadcast over metropolitan police department's city wide channel," Lanier said. The broadcast included a request for the metropolitan police and other law enforcement partners to assist.

They did, and fast. Agencies that responded included the U.S. Park Police, metro transit police, the Naval Criminal Investigative Service, the U.S. Marshals, the Bureau of Alcohol, Tobacco and Firearms and U.S. Capitol Police, in addition to the district's metropolitan police force.

Also in 2013, the responding officers had a hard time figuring out which of the many building on the campus was under attack. This time, responders knew exactly where it was.

"We've learned a lot over the last couple of years, we've exercised hard," said Vice Adm. Dixon Smith, commander of Navy Installations Command.

Beyond the tactical response, the 2013 reviews also found that responders needed to drill in witness management and victim services. Lanier said that the caller had already been interviewed and was determined to not be a hoax, and despite the false alarm, counselors and spiritual support was available to assist employees who may have been at the Navy Yard in 2013, and who found themselves rattled by Thursday's events.

Dixon said even though this call was a false alarm, "We're going to review this again to see what went right and what went wrong and continue to improve upon, improve our procedures in the future."