A large grey dog jumped out of a vehicle on a Surrey street, mauling a 1.5-year-old cocker spaniel-poodle cross and biting a woman who leapt to the dog's aid.

Veterinarians at Surrey Animal Hospital say the dog, named "Louie," was bitten some 15 times on his left side and had a punctured lung and ruptured diaphragm. Staff at first didn’t think he could survive the operation.

“It was very hard. Almost the whole staff cried when we got Louie,” said Ricky Bajwa, the manager of Surrey Animal Hospital.

The other dog appears to be at large – which should be a concern to authorities, she said.

"I’m worried if that dog bit this dog, he can bite someone else’s too. Or even a small child."

Louie was being walked by Terence Burke along 134th Street at 80th Avenue on Friday night at 8:30 p.m. when a brand new yellow Volkswagen Beetle pulled over and the driver and the passenger appeared to be trying to switch positions.

“The dog broke loose, made a beeline right towards little Louie and grabbed ahold of him in a death grip with his jaws,” Burke said. He said he believes the dog that attacked is a grey pit bull.

Burke, who is in his 70s, tried to pull Louie away but there was little he could do.

“I said to myself, ‘He’s going to be dead, he’s going to be dead. It’s a sure thing,’” he told CTV News.

That’s when neighbour Leslie Hayes rushed toward the dogs and attempted to pull them apart. The attacking dog bit her several times on her hands.

“I love dogs. I thought the one was going to get killed, so I just rushed in to save it,” she said.

Hayes said other residents called the police, but by the time officers arrived the attacking dog’s owners and the yellow Beetle were gone.

Burke said he tried to get a licence plate from the Beetle, but it only had a temporary licence.

He said he wants those owners found and taught a lesson.

“It looked like they had no control over their dog whatsoever,” he said.

Veterinarians performed surgery on Louie overnight and it was touch-and-go for some time, said Sandeep Mann.

“I told the owners he was not going to make it. The owners said, 'You should try to save him if you can,'” the vet said. “We tried our best and now he is stable. By tomorrow we’re going to operate on him again.”