The person is walking in the mountains.
A person is outside near nature.
Being in the mountains implies that it is out in nature.
exists e1 x1 x2.(n_mountain(x2) & n_person(x1) & in(e1,x2) & Actor(e1,x1) & v_walk(e1))
exists s1 x1 x2.(near(s1,x2) & n_nature(x2) & Theme(s1,x1) & a_outside(s1) & n_person(x1))