Firefighters are at the scene of a car accident involving two vehicles
two vehicles were involved in an accident.
In both sentence are same. because two vehicles involved in accident.
exists p1 x1 x2.(n_scene(x2) & exists e1 x3 x4 x5 x6.(at(x1,x2) & of(x2,x3) & Theme(e1,x6) & Actor(e1,x5) & v_involve(e1) & n_vehicle(x6) & card_eq_2(x6) & (x3 = x5) & n_accident(x3) & of(x3,x4) & n_car(x4)) & n_firefighter(x1))
exists e1 x1 x2.(in(e1,x2) & n_accident(x2) & Theme(e1,x1) & v_involve(e1) & n_vehicle(x1) & card_eq_2(x1))