'If we do get to somebody in time after they've reached that traditional threshold of death, we can bring them back." – Dr Sam Parnia, intensive care physician. Colin was watching TV on the couch when he had a cardiac arrest. He was 'dead’ for at least 40 minutes before doctors finally brought him back to life. Cassandra was blue and bloated when she was seen floating in the water at a Sydney beach last year. It’s hard to know for sure, but rescuers say she didn’t breathe for at least 15 minutes before they revived her. Both Colin and Cassandra are fine today. Medical science is pushing the boundaries of death, with doctors now to able to resuscitate some patients even an hour after they have 'died'. The consequences of these spilt second decisions can be life-changing – for better and for worse. Speaking to people who have 'come back from the dead’ as well as doctors with conflicting views, Insight examines the latest in medical science and finds out who has the best chance of being revived, and whether we should be reviving people just because we can.