could take steps to help themselves, though they probably don't know it. >> they need to find a watertight door such as this one, that they would close and seal it. >> reporter: former navy diver bobbi seeley showed us where air pockets can be found and how potential survivors could use them. >> when they're in a small compartment like this with an air bubble, they really have to stay calm and breathe shallow and conserve the oxygen in that space. >> reporter: there was an effort to pump oxygen into the korea vessel with the hope that it could create air pockets. but that attempt failed because of bad weather. given those conditions, the cold temperatures and the time elapsed since that ferry went down, the odds for survival here are decreasing, wolf. >> there are other dangers involved in pumping air into a vessel like this. >> this sure are. that navy diver bobbi scully says if a rescue team drills a hole into a compartment that already has air in it, there is a risk of letting air out of that compartment and having the vessel sink even further than it is now. and that could put 2 survivors