Re: Two questions...
Listening to the press conference today, it is apparent that the break-up was not mid-sentence. Columbia continued to transmit for another 32 seconds, but the quality of the data was too low to be displayed and/or broadcast. It is being analyzed, however, and we will undoubtedly learn much from it. Those additional 32 seconds need not have been terrible ones for the astronauts; hopefully whatever caused the transmission to degrade did not effect the crew cabin too badly.
Grieving is,
Nathan.