A contestant riding a pony in a rodeo setting is being thrown by the horse, while another cowboy looks on in the arena and spectators watch from behind a fence.
A contestant riding a pony  is in a rodeo with another cowboy looking at the arena with spectators behind a fence because an accident has happened.
Not all rodeo spectators watch from behind a fence because an accident has happened.
exists x5 x6 x8.(n_arena(x8) & n_cowboy(x6) & n_horse(x5) & all x1.(n_pony(x1) -> exists e1 p1 s1 x2 x3 x4.(exists e3 e2 x7 x9 x10 x11.(r_on(e2) & in(e2,x8) & behind(e3,x11) & n_fence(x11) & r_from(e3) & Theme(e3,x10) & Actor(e3,x9) & v_watch(e3) & (x8 = x10) & n_spectator(x9) & Actor(e2,x7) & v_look(e2) & n_cowboy(x7) & -(x7 = x6)) & while(e1,p1) & Actor(e1,x5) & Theme(e1,x2) & v_throw(e1) & in(x2,x3) & n_setting(x3) & of(x3,x4) & n_rodeo(x4) & for(x2,x1) & n_riding(x2) & a_contestant(s1) & Theme(s1,x2))))
exists p1 s1 x1 x4 x7.(n_arena(x7) & n_cowboy(x4) & a_topic(x1) & exists p2 x2.(exists e1 p3 x3 x5 x6 x8 x9.(in(x2,x3) & with(x3,x5) & exists e2 x10.(Actor(e2,x10) & v_happen(e2) & n_accident(x10)) & because(e1,p3) & at(e1,x7) & with(x7,x8) & behind(x8,x9) & n_fence(x9) & n_spectator(x8) & Actor(e1,x6) & v_look(e1) & (x5 = x6) & n_cowboy(x5) & -(x5 = x4) & n_rodeo(x3)) & n_pony(x2)) & that(x1,p1) & n_riding(x1) & a_contestant(s1) & Theme(s1,x1))