john walsh and jacque picard. don walsh became a friend of mine. he's in the arctic at the age of 80-something. >> here is the interesting thing. we will see this in footage. to go down, you have these things that look like a ballast or something. balloons that are holding it on the surface of the water. it is got so much weight that as soon as you release t hem to come back up, you have weights in there. you have to eliminate them. those weights have not been able to throw them off, you would still be on the bottom of the sea. >> we would not be having this conversation. >> there are little things like that. all of them have to work. >> and typically when things go wrong, it is not one thing. it is several in sequence, because we have thought of one thing. we may have even thought of two things in combination. >> you think of fire, flooding. >> exactly. i call it healthy paranoia. you think for seven years while you are building this thing of all the things that can go wrong and you do the engineering to prevent it, but you cannot prevent everythi