Some people are waiting for a train to pull in, some people are leaving while most are staying.
The people are outside.
Not all people waiting for a train would be outside.
exists e1 e2 p1 p2 x1 x2 x3.(exists e4 x4.(Actor(e4,x4) & v_stay(e4) & n_most(x4)) & while(e2,p2) & Actor(e2,x3) & v_leave(e2) & n_people(x3) & for(e1,x2) & Topic(x2,p1) & exists e3 s1.(a_in(s1) & Manner(e3,s1) & Actor(e3,x2) & v_pull(e3)) & n_train(x2) & Actor(e1,x1) & v_wait(e1) & n_people(x1))
exists s1 x1.(n_people(x1) & Theme(s1,x1) & a_outside(s1))