A man in the red shirt tried to hang onto the rock while three others watched.
That guy is scaling the rock wall.
A guy is a man. Trying to hang onto a rock could be seen as trying to scale a rock wall. Therefore, the man is scaling the rock.
exists e1 p1 s1 x1 x2 x3.(n_person(x2) & n_rock(x3) & n_shirt(x2) & a_red(s1) & Theme(s1,x2) & Topic(e1,p1) & Actor(e1,x1) & v_try(e1) & exists e3 e2 x4 x5.(while(e2,x4) & Theme(e3,x5) & v_watch(e3) & (x4 = x5) & -(x4 = x2) & n_person(x4) & card_eq_3(x4) & onto(e2,x3) & Actor(e2,x1) & v_hang(e2)) & in(x1,x2) & n_man(x1))
exists e1 x1 x2 x3.(n_wall(x2) & of(x2,x3) & n_rock(x3) & n_guy(x1) & Theme(e1,x2) & Actor(e1,x1) & v_scale(e1))