Whakatane, New Zealand (CNN) Geoff Hopkins says he will never forget the cries as the survivors of the White Island volcano eruption were pulled aboard the boat.

Screaming in pain, with skin peeling from their faces and limbs scorched by steam and ash, the survivors were transferred from a dinghy bobbing in the water off the small island.

There was "lots of screaming. Panicked screaming," he says, recalling the injured shouting: "'Get me out of here. I'm burning. I'm burning.'"

The tour boat Hopkins was on had left White Island, off the coast of Whakatane, New Zealand, shortly before the volcano erupted on Monday. Forty-seven people were on the island at the time of the blast. Eight people have so far been confirmed dead.

In the moments immediately after the eruption, the boat's crew made the decision to turn around and help those people left behind.

Geoff and Lillani Hopkins prior to the volcano eruption on White Island on Monday December 9.

"We (could) see there's people in the water. There's people swimming off the island," Hopkins, a New Zealand pastor who was on the vessel for a day trip with his daughter Lillani, told CNN.

The 23 people who were brought on board the boat had "horrific burns," he said.

"A lot of people were in shorts, T-shirts, so their faces, their arms, their hands, their legs (were burned)," Hopkins added. "Skin falling off, and hanging from chins. From fingers. From elbows."

Geoff Hopkins had been on a day trip to the island with his daughter before disaster struck.

The vessel, owned by a company called White Island Tours, was more accustomed to running sightseeing trips than being used as a floating triage center, but as more and more injured people were brought to the boat by dinghies, the crew made a desperate appeal for any doctors on board to come forward.

Hopkins and his daughter are both trained in first aid, and they stepped up to help as the situation unfolded.

He recalled one crew member's expression: "The look of horror on her face as she said, 'We need all the help we can get.'"

As the pair turned from tourists to first responders, he said they focused on those who were most seriously injured.

Of all the people that Hopkins helped, he says one couple has stuck in his mind the most.

US newlyweds Matthew Urey, 36, and Lauren Barham, 32, from Richmond, Virginia, were on the island during a day trip from their honeymoon cruise on the Royal Caribbean vessel Ovation of the Seas.

Photos: An aerial photo shows White Island, New Zealand, after a volcanic eruption on Monday, December 9. Hide Caption 1 of 13 Photos: A makeshift memorial is seen in front of cruise ship Ovation of the Seas, in Tauranga, New Zealand, December 10. There were believed to be at least 30 passengers from the ship taking a tour of the island when the eruption took place. Hide Caption 2 of 13 Photos: Michael Schade, a visitor to the island, captured this photo from a boat, moments after the eruption began. Hide Caption 3 of 13 Photos: Tour operators evacuate tourists from White Island. Hide Caption 4 of 13 Photos: Emergency services attend to a person injured in the eruption, after arriving at the Whakatane Airfield. Hide Caption 5 of 13 Photos: An image from a camera run by the Institute of Geological and Nuclear Sciences (GNS) at the crater on White Island appears to show a group of people close to its rim, just minutes before the eruption. Hide Caption 6 of 13 Photos: Jon Arrieta, who captured this photo of the ash cloud, told CNN he left White Island just one hour before the eruption. Hide Caption 7 of 13 Photos: Coastguard rescue boats arrive at a marina near Whakatane on December 9. Hide Caption 8 of 13 Photos: Tour operators prepare to evacuate visitors who were on the island during the eruption. Hide Caption 9 of 13 Photos: Emergency crews are seen at the Whakatane Airport on December 9. Hide Caption 10 of 13 Photos: A view of the eruption from the sea. Hide Caption 11 of 13 Photos: A rescue helicopter arrives at the Whakatane Airport. Hide Caption 12 of 13 Photos: The eruption on White Island is viewed from the Bay of Plenty coastline on December 9. Hide Caption 13 of 13

"I remember I asked her name and she struggled to say it," Hopkins said of Barham. "And he said it for her and said, 'She's my wife.' And she would ask 'How's my husband? And he would ask 'How's my wife?'"

Their love for each other touched him, and he prayed for them both to survive, Hopkins said.

"There are times when I'm praying," he recalled. "You are not gonna die on this way back. You are not gonna die."

"She said, 'This is the worst day of my life. And I had to say, 'Yes it is. But you've got so much more of your life to live.'"

"When she says 'I don't think I'm gonna make it,' you rebuke that. 'You are gonna make it. You're strong. You're a fighter. You're gonna get through this. You've got a future.'"

Urey and Barham are being treated at two different hospitals, one in Christchurch and one in Auckland.

New Zealand has four specialist burns units, all of which are now full in the wake of the White Island disaster.

A photo taken by Geoff Hopkins on White Island, prior to the volcano's eruption.

"It's absolutely soul-crushing," Janet Urey, Matthew's mother, told CNN via FaceTime. "It's my worst nightmare. But on the other hand I'm trying to focus on the positive."

"I was lucky enough to be notified by Matt that's he was okay," she said. "There were so many families that didn't get any word."

"Minutes could have been life or death for them," Urey added.

"33% of his body is burned," she said. "Many of them are full thickness burns, which are pretty severe. They're going to require plastic surgery, skin grafting."

It was a painful end to what was supposed to be a dream trip.

"It was his trip of a lifetime," she said. "He put so much work and effort and time into planning this to make it just what they wanted. This would be the perfect honeymoon."

CNN also spoke via text message to Barbara Barham, Lauren's mother. She is also traveling to New Zealand to be with her daughter.

"We don't know how she is yet," Barham said. "We don't think she is conscious."

Both mothers are now making the grueling multi-leg trip from the US to New Zealand, with no idea of what awaits them on their arrival.

Correction: This story has been updated to attribute the quote "We need all the help we can get" to a White Island Tours crew member.