Also, the inside passenger capacity is also in question:
https://www.npr.org/2023/06/20/1183273102/titan-missing-sub-titanic-rescue-oceangate
Not only the number of people, but the amount of food and beverages ("sandwiches and water") plus the very small restroom facilities are not conducive for even the short-term ("6 to 8-hour tour") ride to the R.M.S. I betcha this whole arrangement in very close quarters adds to the full uncomfortability in addition to the very little oxygen (which is now harder to maintain) they have to use within this extremely dire situation! 😖😫