I'm sure they were dumping it over the ocean. It takes a lot of time to drain fuel tanks that have been topped off for a transatlantic flight.
Most don't realize that an airplane full of fuel greatly exceeds its max landing weight.
Think about this the next time you're headed down the runway at full throttle preparing to take off. After a certain speed, there's no turning back. The aircraft is simply too heavy to do anything other than get airborne or crash into a giant fireball.
I know that. I just try not to remember it when I'm checking in....