It might be enough. Google says a human needs 300-550 liters of oxygen a day. That equals to about 6.8-12.4 cubic meters of air for the 3 of them for 36 hours.

It might be enough. Google says a human needs 300-550 liters of oxygen a day. That equals to about 6.8-12.4 cubic meters of air for the 3 of them for 36 hours. The space does seem like it could be large enough to hold that much air, especially if it's compressed a little.