SINGAPORE - The mass shooting in Las Vegas was an unprecedented chaotic event, recalled deputy chief Christopher Jones of the Las Vegas Metropolitan Police Department.

With more than 500 injured and at least 58 dead after a gunman opened fire on a crowd of concertgoers in Las Vegas on Oct 1 last year, hospitals there were soon overrun with patients.

Doctors and nurses were also pulled out of the emergency rooms, where they belong, to cope with the scores of incoming patients, said Mr Jones.

This happened despite prior training sessions with the hospitals to prepare for mass casualty events, said Mr Jones, noting that it underscored the importance for inter-agency collaboration, which is a key lesson for Singapore audiences too.

"The time to build those relationships are not during critical events... it's through tabletop exercises beforehand. We have to work through problems before they come up , so everybody knows their role and we can operate better as a team,"he said.

He was speaking at a media interview during the inaugural International Programme on Crisis Leadership organised by the Home Team Academy and US Federal Law Enforcement Training Centers.

Mr Jones, 49, who has been with the police department for 25 years, was one of three speakers who shared their experiences in managing major terror attacks during the three-day workshop held at NTU@one-north.

Another key takeaway that the Singapore authorities can learn from the crisis is the need for out-of-the-box thinking, said Mr Jones.

"Some of the lessons that can be taken out of this are that of preparation, to think beyond what you have thought of in the past... because this was not something we had thought of, and prepare for those things," he said.