Initially it appears they shut down #2 due to a problem with the #2 thrust reverser. If you watch the N1 indications and the throttle positions (graphs at the right) you cans see that as they turn final, they are adancing the #2 throttle (with 1 and 4) rather than #3. It appears they caused the ac to be two engine vice three. Also, they did not retract landing gear at any point (though I have no idea how much drag that would add to an ac that big).