People are dressed in costumes while on a boardwalk.
People are on their way to a costume party
The fact that people are dressed in costumes doesn't imply people on their way to a costume party.
exists e1 x1 x2 x3.(on(e1,x3) & n_boardwalk(x3) & r_while(e1) & in(e1,x2) & n_costume(x2) & Theme(e1,x1) & v_dress(e1) & n_people(x1))
exists p1 x1 x2.(exists x3 x4.(on(x1,x2) & to(x2,x3) & n_party(x3) & of(x3,x4) & n_costume(x4)) & n_way(x2) & of(x2,x1) & n_thing(x1) & n_people(x1))