What would you have done if you encountered or witness such a mindless attack ? Attack on Melbourne subway.
From most of the comments, it is understandable that no one wants to be a hero and become a zero unless he/she is confident of handling the situation. However from the posts of a majority commenters, to label certain groups of people as having hatred for certain race or blaming the government for its emigration policy is both ridiculous and backward looking. Without emigration and foreign labor, aus will not be able to maintain its competitiveness to keep up with the global economy. People need to consider the fact that anyone from any races are equally guilty of heinous crimes. Take the mindless attack on other races by a group of rural youths at Australia day 2009 , the cronulla riots and subsequent pelting of eggs..
Unfortunately, safety can only enforced by having adequate resource of policing or security resources, adequate meting out of justice and regulations (not the promotion of drug needle centers) , better security machinery and thorough emigration checks (not only for asylum but also for work visas). Until enough effort is made, Aus will remain as one of the top crime-ridden country in the world.
With my recent post on the ATM bandits saga, there is now a clear and imminent present danger which may hit the streets - and that is to do with identity theft. In this 
There is an interesting read