System scavenging.
Pull from unused monitors and computers to keep life support functioning.
MIR is a good example of what and how they did that.
My idea was that water was leaking from the center (a lot of the water from condensation as life support systems ) outward due to the centrifugal gravity and had created a deep pool in the last habitat with the escape capsule docked at the bottom of that.
You are right though. I was just going through it too fast. I’ll make it longer.