One mallard dropped out of the action and the remaining male pushed her underwater again. At this point I got distracted by a kingfisher that flew by making a racket. When I turned my attention back to the ducks, the female had climbed out on the bank and the male was still in the water. So she was ok. I went off to pursue the kingfisher.
Male Mallards (Anas platyrhynchos)
Female Domestic Duck (Anas platyrhynchos domesticus)