those trying to cut into it. >> absolutely. even an rov, even though there aren't people in it, you don't want to lose the rov. you have to be careful always of what's around you, all the wreckage, the electrical wiring, the broken debris. manned submarines even more you have to be, because they are manned. you don't have the problem of the umbilical catching up in the wreckage. >> reporter: what we're in works autonomously. we can float andaman ufr our sells. we don't have to worry about a long cable going all the way to the surface. that said, there are still dangers. once we become trapped, who is coming to get us? >> another rov or submersible that can free you, finding out what's holding it down or free you. it's not a pleasant job. it's a very painstaking one. with the upwelling of the silt every time you move regardless of what sort of vehicle it is.