One of the problems when working at 5,000 ft is the overwhelming pressure. Something along the lines of 5,000 psi. Trying to inflate anything is nearly impossible, what with the amazing atmospheric pressure at that depth.
I would pay $1000.00 to hear the CEO of BP directly blame this fact on the owners of this delay of a fix.
How long would it take to stop a leak at 120 feet or on land?