I had trouble locating the pipes to be fixed the first couple of times. You should have (I think) 5 pieces of rubber tubing. I finally decided to save - forget about solving it right away and just locate all the broken pipes. Once you have those earmarked - re-load and focus on what fixes what. The pieces do have slight variations that you will notice after a while. Then I reloaded and fixed them fast ran into the gear room and up the ladder and removed the tank. Now breathe deep.
I also used just lung pwer for all the earlier stuff with the octopus and grabbing the rubber hoses. I went back up the stairs after each and took a new deep breath. The saved all my O2 in the tank for the submerged room and the gear underwater stuff. I had plenty of air to finish.
Course - this all took a little bit of time and a lot of saving and re-loading. You can save in the submerged room as well.