When Lachlan Cook died after a school trip, the 'world stopped' for his family. They are still fighting for answers

With only enough room in the air ambulance for one parent, Kirsten McMahon took the seat next to her son's body and braced for the long flight back to Melbourne.

The plane was tiny but her hopes, that doctors at home would be able to perform a life-affirming miracle, were immense.

But when they arrived on the 18th floor of the Royal Children's Hospital, she was met with condolences.