Lowest point, theoretically would be below the level of the Dead Sea, and typical air pressure at the Dead Sea is about 15.44 PSI. Might actually make for relief for people with breathing problems, but extended stay, then making a sudden departure/evacuation, could still potentially cause Nitrogen Narcosis/‘The Bends’, as nitrogen accumulates over time, relative to increased pressure. Without study and documentation, I won’t hazard a guess as to the potential need for decompression, across potentially months of habitation at depth.
With diving (out of date and practice, but I am a PADI certified Openwater Diver), Nitrogen Narcosis occurs faster, due to extreme pressures involved.
Another aspect worth noting is the extra training of personnel, for even going into the depths of the Troll A platform, as documented partially, in the following music video/documentary. SHOULD there be a structural failure, odds are it would be catastrophic and kill all but a few of the upper area occupants.