Been reading The Hail Mary Project by Andy Weir and I’m my brain is seeing everything in terms of space craft and connecting airlocks now.
So imagine you had a earth spacecraft with lots of air supplies stored in liquid form that is parked next to an alien ship that was basically an low pressure, infinitely expanding balloon.
Then if someone built a connecting tunnel between them and opened the airlocks at both ends. Let’s call that the airlock tunnel Strategy.
The air would flow between them, the balloon ship would expand. The airlock would get very windy and even hot. Meanwhile the pressure sensors on the earth ship would sense the pressure drop and open the stored reserves to replenish it. There would probably be some alarms too.
Eventually there’s no more stored air, pressure equalizes on both sides and you have two pressurized craft.