An astronaut and a diver are underwater.
Two friends are swimming.
Just because the astronaut and the diver are underwater doesn't mean that they are friends.
exists p1 x1 x2 x3.(exists x4.((x1 = x4) & n_underwater(x4)) & subset_of(x3,x1) & n_diver(x3) & subset_of(x2,x1) & n_astronaut(x2))
exists p1 x1.(exists x2.((x1 = x2) & n_swimming(x2)) & n_friend(x1) & card_eq_2(x1))