Laurel Silver-Valker's sons never worried about their mother scuba diving.
"It brought her peace," Alex Valker said
She was an educator from Tustin, and an experienced diver.
"She was a teacher at life. This whole place is a classroom for her," her son said.
On December 29, 2015, she was embarking on nearly her 1,000th dive.
It would be her last.
Laurel was lost at sea.
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"It was a shock," her son Graham Valker said.
"When my father told me she was missing -- I no longer felt her, she was gone," Alex said.
Laurel went on a diving trip with Sundiver Express -- a regular. She sometimes volunteered as a crew member.
It was bright skies and calm seas as they left long beach headed to Ship Rock, the first dive site.
Attorney David Rose, defending Sundiver in a civil lawsuit, acknowledges the captain helped Laurel into the water.
"She watched her descend 15-20 feet. Laurel gave the thumbs up," Rose said.
That was the last time Laurel was seen alive.
The captain is responsible for everyone who steps onto their boat," said Jeffrey Salberg, attorney for Laurel's sons.
NBC4 obtained Coast Guard documents that confirm Laurel's name was not on the initial passenger roster.
It is the very same list used to make sure that all divers are out of the water and back on the boat.
It wasn't until the boat reached a second dive location that the crew noticed Laurel's gear was not on board and she was nowhere to be found.
"It didn't have to end this way," Salberg said. "The fact that they are still operating is a travesty."
Salberg points to another incident where a diver was stranded at sea.
The dive was run by a separate charter company but it was a Sundiver ship -- and a Sundiver captain.
Sundiver attorney's Rose says the charter rented the entire boat and was running the dive.
"It was their trip tour and roll call procedures. Since that incident - they don't do that anymore - the boat, the captain is responsible for making sure the roll calls are handled properly," Rose said.
Dan Carlock told the Today Show how he survived five hours drifting in the water before being rescued by Boy Scouts on a sailing trip.
"I was getting the chills...shivering a bit," he said on the program.
Laurel would not be so lucky.
When questioned by NBC4 who is responsible for Laurel's death, Sundiver's attorney responded: "Good question. Not my clients...I think it's an unfortunate accident."
Rose argues that diving is "inherently dangerous" and Laurel was in no shape to dive that day.
"She had a half hour sleep the night before - that is not conducive to a safe dive," he said.
Rose says she made multiple risky decisions.
"She was diving without any buoyancy vest that day," Rose said. "She was not diving with a buddy - and she was going deep and she had no surface signaling device."
Laurel suffered from fibromyalgia. Diving deep relieved her chronic pain.
"She had no pain when she was in the water," her son Graham said.
Laurel's body has never been recovered.
When asked if it would give her sons a sense of comfort if she was found, Graham said no.
"The ocean is her home," he said.