waits so long because it's just a normal confusion of the moment. but at some point in all of this, an air traffic controller can push the big red button that says help, panic, missing plane. and that's what they didn't do until much later. >> not until four hours after it's clear the plane is lost did air traffic control notify emergency responders. >> that just is so painful to think about, that four hours later, no one's looking yet. >> as precious hours pass, time is running out. while flight 370 flies further and further over one of the world's largest oceans. coming up, what happened onboard flight 370? >> we do not know who the