The decision to storm the Sydney, Australia, café that had been the scene of a 16-hour hostage siege is not a sign that negotiations had failed to serve any purpose, former hostage negotiators say.

Police raided the Lindt Chocolat Café after they heard a number of gunshots from inside. Three people were killed — the gunman and two of the hostages — and four others were wounded. Before the raid, negotiators had been in contact with the gunman, Man Haron Monis.

"One of the pet peeves of mine is you may hear some say that negotiations failed so they had to take this action. Well negotiations didn’t fail, negotiations buy time," said Gary Noesner, the former chief hostage negotiator for the FBI.

"That purchase of time normally leads to a very positive outcome in the 90 percentiles. But it doesn’t always because the perpetrator, with the passage of time, could become more fatigued, more stressed, less co-operative more desperate. It's very dependent on the facts and circumstances of the incident."

'Not everyone makes the right decision'

Hostage-takers feel empowered because they are holding hostages and believe they can get whatever they want, Noesner said. But as time passes and the difficulty of getting their objectives met becomes apparent, the majority of hostage-takers will choose to surrender rather than run the risk of being seriously injured or killed.

"But not everyone makes the right decision," Noesner said. "The outcome is really determined by the perpetrator."

In this case, Monis was obviously a troubled soul, a paranoid angry person who had been in conflict with the police before, Noesner said.

"These people are very difficult people to deal with," Noesner told CBC News.

Frank Bolz, who helped form the New York City Police Department's hostage negotiating team and became its commanding officer and chief negotiator, said had there been no negotiations and police stormed the cafe immediately, more lives might have been lost.

Bolz, who was involved in 285 hostage-takings and helped bring about the safe release of 850 hostages, said the whole principle of using time is to ensure that violence is a last resort.

'Don't want to go in there and precipitate it'

"However, the capacity to resort to that violence must be there," Bolz said. "Because we can't stand by if [the hostage-taker] starts to kill people, [but] we don't want to go in there and precipitate it. The words we used to say: ‘We may never make the job any better but we don’t want to make it any worse.'  That’s why we use time."

However, knowing when it's time to end negotiations is situational. Part of it, Noesner said, is "gut instinct" but it's also working with the team, determining whether the crisis has steadily improved or become less stable and more dangerous.

An increase in violent language by the hostage-taker, such as an increase in threats, might indicate it's time for police to move in. Conversely, a hostage-taker who appears less violent, more co-operative and has let some hostages go might suggest to stay the course with dialogue.

Will Geddes, a counter-terrorism expert and hostage negotiator, said it's time to end negotiations when communications have ceased and the hostage-taker is no longer willing to communicate any further or in any kind of rational sense.

"Or when you feel the hostages lives are at such significant risk that to not intervene at this particular time with some kind of recovery or assault team could endanger them even either further or you are on that point of no return," Geddes said.

Noesner said it's rare that the situation remain neutral. Either negotiators will see slow steady progress toward improvement or, as in the case in Sydney, police must take action.

"Those gunshots that they heard in conjunction with whatever dialogue or lack of dialogue they were having no doubt led them to assess that the situation is less stable, more dangerous and therefore that mitigates toward at least making an assessment to save lives rather than sit back and watch this guy just murdering people," Noesner said.

Bolz said in the Sydney case, police were very disciplined, but when they heard shots, they "apparently believed the lives of the hostages were in danger, and they had to go in there and do something."

With files from The Associated Press