last 48 hours as a precaution. they want to measure the levels, the oil pressure levels, throughout the entire time in six hour increments to make sure they're not approaching dangerous levels that would indicate a breach in the well or a problem with the cap. if it's able to hold up to the pressure during the 48-hour time, at that point, they'll make the decision to either just leave the cap in place as essentially a cork in the well, or if there are signs of weaknesses where they continue funneling oil up to ships on the surface, and contain the oil that way, but in theory, if all goes well, virtually no additional oil will leak into the gulf from this point. >> shepard: what are they going to do if somewhere between the floor of the gulf and reservoir of oil, some, i don't know, three miles below that, that well core ruptures and oil