The young ride attendant working the Thunder River Rapids at the time of the Dreamworld tragedy tried desperately to save people from the disaster, an inquest has been told.

Courtney Williams, a level two operator on her first week on the Thunder River Rapids, was on duty at the off-loading station just metres from where Kate Goodchild, Luke Dorsett, Roozi Araghi and former Kawerau woman Cindy Low were hurled from a raft to their deaths in October, 2016.

The opening day of an inquest into the tragedy yesterday revealed for the first time the actions of Williams on the day, including her heroic response to the horror in front of her.

After raising the alarm with senior ride operator Peter Nemeth, she rushed to help amid the terrifying scenes.

Senior police investigator Detective Sergeant Nicola Brown yesterday told coroner James McDougall that Williams went in to ''emergency mode'' and rushed to the aid of Low's son Kieran who, with Goodchild's daughter Ebony, had miraculously been thrown clear of the raft as it suddenly lurched up on its axis.

"[Williams] went into emergency mode and assisted everyone she could, including Kieran, out of the ride," Brown said.

Although Williams was only on her first week operating the Thunder River rapids, she had level two operator qualifications and was considered a competent ride attendant who had been at the theme park for almost two years.

Level one operators usually performed restricted roles such as ushering guests on and off attractions.

Staff rallied around Williams after the tragedy and she was provided counselling for the ordeal.

She returned to the park for the harrowing task of assisting detectives in a walk-through of the scene, but no longer works at Dreamworld. Nemeth transferred to a position at Dreamworld's sister park WhiteWater World.

A former co-worker told the inquest the tragic events of that day had affected Williams.

"She was really cut up about it," the co-worker said.

Death 'could have been prevented in two seconds'

Details of Williams' heroics come amid reports the four tragic deaths could have been avoided if an emergency button had been pressed.

An operator had access to the button, which was designed to stop the ride within two seconds, but said she didn't know what the switch did, the inquest heard yesterday.

Steven Whybrow, the barrister for Goodchild and Dorsett, said the button was not clearly labelled, the ABC reported.

"She was told not to worry about that button, no one uses it?" Whybrow asked.

"Yes," Brown responded.

Brown said the operators managed the ride from a control panel elsewhere, which only had a "slow" stop button, which took "approximately seven seconds" to stop the ride.

A memo had been sent to Dreamworld staff days before the tragedy, warning the emergency stop button was not to be pressed except in certain specific circumstances.

Brown told the inquest the pump failed at 11.50am and then again at 1.09pm and was reset both times.

"There's no evidence any engineering staff attended the second incident," Brown said.

"Nothing else seems to have been done apart from resetting the pump."

She said multiple safety recommendations such as the inclusion of an emergency stop button on the main control panel and the installation of CCTV footage for the unloading area operator were not implemented.

Senior Constable Steven Cornish told the inquest the ride lacked automatic safety features such as a water level sensor, which would have prevented the tragedy.

He said the pushing the emergency shutdown button at any time from the failure of a water pump until the rafts collided would have also ensured no loss of life.