One person is exiting the bottom of a long escalator while another has just entered at the bottom.
Some people are on an escalator.
One person is exiting an escalator while another is just entering at the bottom so some people are on an escalator.
exists e1 p1 s1 x1 x2 x3.(n_bottom(x2) & n_bottom(x2) & exists e2 s2 x4.(a_just(s2) & Manner(e2,s2) & at(e2,x2) & Actor(e2,x4) & v_enter(e2) & n_thing(x4)) & while(e1,p1) & Theme(e1,x2) & Actor(e1,x1) & v_exit(e1) & of(x2,x3) & n_escalator(x3) & a_long(s1) & Theme(s1,x3) & n_person(x1) & card_eq_1(x1))
exists p1 x1.(exists x2.(on(x1,x2) & n_escalator(x2)) & n_people(x1))