up, i'm sure that is weighing heavily on the rescuers and whether or not they have a back-upset of rescuers -- back-up set of rescuers remaining to move through the system today. >> paul, it is remarkable to think of the logistics of this and we should pause for a moment and remember the rescue diver who died trying to set up oxygen tanks for the rescue and ran out of air himself. this is a lot of time to prepare and then painstaking removal of the divers. a lot of folks involved. talk to me about your perception of the logistics here. >> the logistics in the case are unheard of for this type of operation. they're not unheard of in the cave diving world. there are a number of divers