Ahead of the ill-fated submersible trip on Sunday, Suleman Dawood was said to be "terrified" to go on a dive to see the wreck of the Titanic.

The 19-year-old told a relative that he "wasn't very up for it", according to his aunt, Azmeh Dawood.

In an interview with NBC News, she said he agreed to go on the Titan submersible trip with his dad to please him and bond with him on Father's Day — the day the submersible they were in was first reported missing in the North Atlantic.

Azmeh said her brother, Shahzada Dawood, who was Suleman's father, had been obsessed with the Titanic since childhood.

"I am thinking of Suleman, who is 19, in there, just perhaps gasping for breath...It has been crippling, to be honest," a heartbroken Azmeh told NBC News.

Suleman was the youngest of five people on board the Titan.

He was a first-year Strathclyde Business School student at the University of Strathclyde, according to the BBC.

On Thursday, the US Coast Guard said the missing submersible had imploded, killing all its passengers.

Unlike an explosion, an implosion is caused by external pressure crushing in. In both instances, there is unlikely to be much left of a vessel or its cargo.

Submersibles are designed to withstand the immense underwater pressure on the floor of the ocean.

In an implosion caused by a defect in the hull or for some other reason, the submersible would collapse in on itself in milliseconds, crushed by the water pressure, according to Scientific American. This would also mean instantaneous death for those inside.

"If you gave me a million dollars, I would not have gotten into the Titan," Azmeh told NBC.

ALSO READ: James Cameron says he wishes he'd sounded alarm over lost submersible

This article was first published in The Straits Times. Permission required for reproduction.