Someone is running down the side of a mountain.
They are running from a bear.
Someone running on a mountain does not imply that they are more than one person. A person can run down a mountain without running from a bear.
exists e1 s1 x1 x2 x3.(n_side(x2) & a_down(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_run(e1) & of(x2,x3) & n_mountain(x3) & n_person(x1))
exists e1 x1.(from(e1,x1) & n_bear(x1) & Actor(e1,x1) & v_run(e1) & n_thing(x1))