Apparently they have a deep sea pipe-laying vessel on hand so there's hope yet.
//Expert says vessel being trapped in Titanic shipwreck could help not hinder rescue
One of the best-case scenarios that might have happened to the Titan would be if it has been entangled in the wreckage of the Titanic, an ocean explorer and expert has said.
If that's the case, it could make the submersible with five people aboard easier to find, Tim Taylor, an ocean explorer and the CEO of Tiburon Subsea, told Sky News' US partner NBC News.
"Lifting the submarine off the bottom is not as hard or difficult as one may think if it's still intact," Mr Taylor said.//
https://news.sky.com/story/titanic-submarine-missing-live-updates-submersible-cannot-be-opened-from-inside-time-running-out-on-oxygen-supply-waiver-mentions-death-three-times-12905748