i would love to see that your spacesuite has an oxygen tank wich can and will run out. then you will die. of courso that would be really unbalanced so you would be able to make a suite refill station and oxygen collection and distribution. connected by pipes and wires. that would mean that if you have a completely ceiled off area that you would no longer need to wear your space suit because you are just able to breath in that area. the oxygen will escape by breaking hles in the walls into outter space. also open doors will count as a hole. that way with doors you are able to make airlocks. also that system will require power ofcourse so that its not free. the oxygen collectors would need blocks like leaves and grass surrounding it so it would be able to get the oxygen from there. the last thing are oxygen pipes. oxygen is being transfered from the oxygen collectors to the distributers through the pipes.