A person in black has just stepped off of the escalator.
a black person got off the escalator to go to a meeting
A person wearing black does not imply the person is black.  Stepping off the escalator does not imply they are going to a meeting.
exists e1 s1 s2 x1 x2 x3.(n_escalator(x3) & a_just(s2) & Manner(e1,s2) & of(e1,x3) & r_off(e1) & Actor(e1,x1) & v_step(e1) & Theme(s1,x2) & a_black(s1) & (x1 = x2) & n_person(x1))
exists e1 p1 s1 s2 s3 x1 x2 x3.(n_escalator(x3) & Topic(e1,p1) & exists e2 x4.(to(e2,x4) & n_meeting(x4) & Actor(e2,x1) & v_go(e2)) & a_off(s3) & Manner(e1,s3) & Theme(e1,x3) & Actor(e1,x2) & v_get(e1) & n_person(x2) & a_black(s2) & Theme(s2,x2) & n_person(x1) & a_black(s1) & Theme(s1,x1))