People standing in front of mechanical equipment.
The people were male.
Not all people are male, and there is nothing to imply they are standing in front of mechanical equipment.
exists e1 s1 x1 x2 x3 x4.(a_topic(x1) & in(e1,x3) & of(x3,x4) & n_equipment(x4) & a_mechanical(s1) & Theme(s1,x4) & n_front(x3) & Actor(e1,x2) & v_stand(e1) & (x1 = x2) & n_people(x1))
exists s1 x1.(n_people(x1) & Theme(s1,x1) & a_male(s1))