About 18 months ago, on an otherwise quiet family evening, Suzie Lyons' young son broke out in a rash and couldn't breathe properly. As the boy's condition deteriorated, Lyons became so concerned that she drove him to the nearby Sydney's Childrens Hospital.

To her horror, access to the hospital emergency department appeared to be blocked by construction. Eventually she found her way past wire fences and traffic barriers to a doctor, who told her that her son's previously undiagnosed nuts allergy had triggered an anaphylactic shock.