2014 Sydney hostage crisis
The 2014 Sydney hostage crisis, also known as the Sydney siege and Lindt Cafe siege, occurred on 15–16 December 2014 when a lone gunman, Man Haron Monis, held hostage ten customers and eight employees of a Lindt chocolate café located at Martin Place in Sydney, Australia. Police treated the event as a terrorist attack at the time, but Monis' motives were subsequently debated. However, the findings of the Coroner in 2017 deemed the event to be a terrorist attack.
Sydney siege inquest
Army advisors were concerned that the high velocity 5.56mm bullets could fragment and kill hostages. For close range operations like this they would have used larger but slower 9mm bullets. They complained about a lack of cooperation from the NSW Police. The army had gained substantial experience of these types of operations in Afghanistan. 
After some hours of negotiation, police withdrew their attempt to keep their actions during the siege discussed in camera. However, issues dealing with "methodology" would be secret.
Superintendent Allan Sicard said that he "was OK" with allowing Monis to speak on ABC radio in exchange for hostages early during the siege. It is unclear why this did not happen.