A man in a black shirt stands in front of an emergency vehicle.
A man wears a black shirt because it is part of his uniform at work.
Just because a man is in front of  an emergency vehicle it does not mean he is at work.
exists s1 x1 x2 x3 x4 x5 x6.(a_topic(x1) & in(x1,x2) & in(x2,x4) & of(x4,x5) & n_vehicle(x5) & of(x5,x6) & n_emergency(x6) & n_front(x4) & n_stand(x2) & of(x2,x3) & n_shirt(x3) & a_black(s1) & Theme(s1,x2) & n_man(x1))
exists e1 p1 s1 x1 x2 x4.(exists p2 x3 x5.((x1 = x3) & of(x3,x4) & at(x4,x5) & n_work(x5) & n_part(x3)) & n_uniform(x4) & of(x4,x1) & n_male(x1) & n_thing(x1) & because(e1,p1) & Theme(e1,x2) & Actor(e1,x1) & v_wear(e1) & n_shirt(x2) & a_black(s1) & Theme(s1,x2) & n_man(x1))