People are dressed in costumes while on a boardwalk.
People are outside
The people are on a boardwalk so they must be outside.
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 s1 x1.(Theme(s1,x1) & a_outside(s1) & n_people(x1))