Dreamworld medic was resuscitating victim when the sinking water revealed another person.

Not even the best surgeons in the land would have been able to save those injured in Dreamworld’s 2016 Thunder River Rapids ride tragedy.

The former first aid manager of the Gold Coast theme park has told an inquest into the deaths of four visitors at the park that nothing could be done to save their lives.

Cindy Low, Kate Goodchild, her brother Luke Dorsett and his partner Roozi Araghi all died when the 30-year-old ride malfunctioned, causing their raft to collide with another raft before flipping on its side.

Ex-first aid manager and qualified paramedic Shane Green was among the first to arrive on the scene but told the inquest in Southport his staff were essentially confronted by a hopeless scene.

“In all honesty, if we’d have had the world’s leading cardio-thoracic surgeons, neurosurgeons and trauma surgeons in the park with all their equipment, nothing would have changed the outcome,” he said on Wednesday.

Mr Green said safety staff at the park had never contemplated such a situation.

“We’d do a lot of training, different things – cardiac arrest training – but we’d never trained, or even thought about anything like that,” he said.

Mr Green conceded the scene had appeared “chaotic and out of control” due to the overwhelming nature of the tragedy.

Both Mr Green and another of the park’s former safety officers, paramedic John Clark, told the inquest they were only initially aware of three victims.

As Mr Clark attempted resuscitation on one person he’d dragged from a water-filled trench, he became aware of a fourth person in the trench as the water receded.

He was unable to tell the inquest how long he’d been working on the victim when the other victim was revealed.

“If I was to tell you a time I’d be completely guessing,” Mr Clark said.

Mr Green said the failure to locate the fourth victim showed in hindsight there could have been improvements on how staff assessed emergency scenes.

“I’d have to say yes because there was a patient under the water and we weren’t aware,” he said.

Mr Green, Mr Clark and fellow former employees Rebecca Ramsey and Paul Burke are all suing Dreamworld for compensation for the psychological trauma they suffered.

The inquest was also shown a letter from a Dreamworld staff union representative to senior management advising the park to eliminate human error or simplify shutdown procedures on rides before the tragedy.

The letter was sent after a similar incident in November 2014 on the Thunder River Rapids ride where two rafts carrying visitors collided.

The letter states the reliance on staff to shut down rides in emergencies increased the likelihood of incidents and it was advisable to “eliminate human error”.

It suggested the park should have just one button for staff to hit in an emergency shutdown.

Former employee Stephen Buss, who was sacked after the 2014 incident, said hearing about the tragedy had confused him.

“I don’t know why (the ride) wasn’t stopped,” he said, adding emergency shutdown procedures had been “drummed” into staff as part of their training.

The inquest continues on Thursday.