The family of two of the victims from the Dreamworld tragedy say the death of their loved ones have "throttled" them and they hold the theme park completely responsible.

Kate Goodchild and Luke Dorsett's father, Shayne Goodchild, and Ms Goodchild's partner, David Turner, released a statement on the fifth day of the inquest into their deaths on the Thunder River Rapids ride.

"We are tired and devastated and horrified by the evidence that has come out this week," the family members said.

"We hold Dreamworld totally responsible for this tragic event that could have so easily been avoided.

"It has throttled our family."

In a statement, Dreamworld CEO Craig Davidson said his thoughts remained with the families of the victims.

"We understand that this has been a harrowing week for them and that they are devastated and horrified," Mr Davidson said.

"We share those feelings. We are truly sorry this happened.

"It is our aim to assist the coroner as best we can to help understand how this tragedy occurred, and what we can do to ensure it never happens again."

'Almost identical' collision two years ago: inquest

Earlier, the inquest heard an "almost identical" collision occurred two years prior and a ride operator was fired.

Kate Goodchild, Luke Dorsett, Roozi Araghi and Cindy Low were killed when they were thrown from a vessel on the Thunder River Rapids ride in October 2016.

Dreamworld ride operator Chloe Brix worked on the Thunder Rapids Ride. ( AAP: Darren England )

The inquiry heard a large water pump feeding the ride broke down, water levels dropped and a raft got stuck on the conveyor before two vessels collided.

Dreamworld employee Chloe Brix worked on the ride regularly and told the inquest she heard "through gossip" that a ride operator was terminated in November 2014 because of a safety issue but was never told by management what exactly had occurred.

Barrister Steven Whybrow, for Kate Goodchild and Luke Dorsett, told the court it was "an almost identical incident of rafts coming into contact" after a pump had gone off.

"I'll suggest this is what apparently had occurred," Mr Whybrow said.

"The operator … shut down a pump on the Rapid ride without verifying the location of all of the rafts.

"This led to a situation where a raft containing guests bottomed out at the top of the conveyor due to a lack of water supply.

"An additional raft containing guests has then collided with it which, continued to be pushed by the conveyor until the conveyor was shut down.

"Are you aware of that incident?

"No," Ms Brix replied.

"You were just made aware that he had not followed procedure about stopping and starting up pumps?" Mr Whybrow asked.

"Yes."

Roozi Araghi, Luke Dorsett, Kate Goodchild, and Cindy Low lost their lives on the ride. ( Facebook )

Fitter called to about '20 ride shutdowns a day'

The inquest heard the park's technicians were not taught how to assess whether a ride fault could be dangerous.

Dreamworld fitter and turner Matthew Robertson said he had to use his own judgment to decide whether a fault was dangerous.

Mr Robertson told the inquiry during busy periods he could be called to about 20 ride shutdowns in one day due to faults.

He said that on the day of the fatal incident he was called to the Thunder River Rapids ride twice because of pump failures.

He said guests were getting "irritable" after the first pump failure at 11.50am because of the time it was taking to evacuate them off the ride and get it fixed, so he asked the electrical department how to reset the pumps himself.

"I thought if we knew and were allowed to reset them, it might speed the process up," he told the court.

Counsel assisting the coroner Rhiannon Helsen asked Mr Robertson if the electrical department was "stretched quite thin" on the day of the fatalities and he replied "yes, that's correct".

"The electrical team were distracted that day due to other issues they needed to attend to in the park," he said.

Mr Robertson testified he helped reset the pump after the second breakdown and told a supervisor the entire ride should be shut down if it happened a third time.

He told the court he had never been told by management that rafts had previously flipped on the ride.

The inquest heard on Thursday that a senior ride operator had not participated in any emergency drills or simulations since the fatalities in 2016.

Prior to the event there was also "no scenario training" from Dreamworld to deal with an event of rafts being stranded on a conveyor belt.

The court also heard there was no alarm to signal when a pump had malfunctioned on the Thunder River Rapids ride.