Those who step foot on board the Titanic submersible are warned there is a 'great danger' they'll be 'cut in half' before setting off.
Channel 5 were broadcasting its documentary after it was confirmed the debris field found earlier near the wreck of the ancient ship has been confirmed as belonging to the missing Titan submersible, with all five passengers declared dead.
Before the heartbreaking announcement, Dan Walker spoke to expert Martin Phillips, who has previously undertook a similar trip.
"The risks and spelled out for you, you are well aware," the journalist said. "You are told in no uncertain terms.
"There is a great danger of fire, and the pressure down there because of the atmosphere – even if you get a pin prick in the capsule the water being forced through would be like a laser cutting you in half.
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"But they say don't worry you won't know about it. They really laid it on the line."
Jacquie Goddard, a correspondent for the Times in America said there is a chance those on board have conserved oxygen – despite reports the supply has already run out.
She told Dan Walker: "Maybe, just maybe, there were innovative enough to have preserved some of that supply.
"Maybe some of the bangs that they say they heard shows there's life still down there. People know the reality but they are not ready to give up but they are clutching at miracles."
OceanGate's Titan lost contact with the company on Sunday and a race-against-time search was launched for the submersible, which is believed to have now run out of oxygen.
Today, "debris field" has been discovered within the search area in the hunt for missing vessel.
It was found by a remotely-operated vehicle on the seafloor near the Titanic and the findings are being 'evaluated' by experts.
Admiral Sir James Burnell-Nugent, former Commander-in-Chief Fleet of the Royal Navy, told Sky News that "the nature of the announcement suggests this debris is in some way connected with the Titan".
He explained: "There is of course a large debris field around the Titanic – and the various things we've seen retrieved from the Titanic have come from the debris field. It covers several hectares.
"But I think if this was Titanic debris, the Coast Guard would have made a distinction in the announcement. I think on balance this is probably grim news and suggests the Titan might have imploded under the immense pressure of the seawater while it was on its way down."
Documents show OceanGate was repeatedly warned that there might be catastrophic safety problems posed by the way it was developed.
Rescuers have rushed ships, planes and other equipment to the site of the disappearance. On Thursday, the US Coast Guard said an undersea robot sent by a Canadian ship had reached the sea floor, while a French research institute said a deep-diving robot with cameras, lights and arms also joined the operation.
The vessel was about 435 miles south of St John’s, Newfoundland, during a voyage to the Titanic shipwreck off the coast of Canada.
Founding member of the Board of Trustees of The Explorers Club, Hamish Harding, was on board the undersea craft, alongside UK-based businessman Shahzada Dawood, his son Suleman Dawood, and OceanGate’s chief executive and founder Stockton Rush, as well as French submersible pilot Paul-Henri Nargeolet.
Sidonie Nargeolet, Paul-Henri's daughter said: "If they are not found, it will be very sad for us because we will not see him again"
"What he liked the most was to be in a submarine, (near) the Titanic. He is where he really loved being. I would prefer him (dying) at a place where he is very happy."
Nargeolet was a renowned diver.
