Since the whole crew cannot be evacuated st once, I wonder if they would take air tanks with them to replenish the oxygen supply within the submarine as they bring personnel up to the surface.
I would think they would be able to do something like that - maybe personal air supplies (tank/mask). Taking crew members out will reduce the load on what oxygen supply is left, too.
I hope they’ve truly found the sub and if so, can get to the crew in time.