"Mr Pogue said yesterday he had been told that there were seven ballasts that the submersible could jettison to float to the top.

‘Either they are bobbing on the surface and have no power,’ he told Chris Cuomo on NewsNation.

'Or something happened that overrode all seven of those ballasts.

‘Or the really horrible possibility is the capsule developed a leak, and they’d be dead in a fraction of a second.’"

When I originally read it, the source was not the daily mail, but this article mentions it. https://www.dailymail.co.uk/news/article-12213755/Missing-Titanic-sub-no-escape-pod.html