Four people climbing metal stairs on a metal structure.
People are on an elevator.
The people can't be on an elevator while climbing stairs.
exists e1 x1 x2 x3 x4 x5 x6.(a_topic(x1) & on(e1,x5) & n_structure(x5) & of(x5,x6) & n_metal(x6) & Theme(e1,x3) & Actor(e1,x2) & v_climb(e1) & n_stair(x3) & of(x3,x4) & n_metal(x4) & (x1 = x2) & n_people(x1) & card_eq_4(x1))
exists p1 x1.(exists x2.(on(x1,x2) & n_elevator(x2)) & n_people(x1))