A man with an arm cast films something on video while another man is looking at the camera.
A man films a video of a dog walking down the sidewalk while another man watches.
Just because the man films something does not mean that he films a video of a dog walking.
(-x)
exists x6.(n_sidewalk(x6) & all x1.(n_video(x1) -> exists e1 p1 s1 x2 x3 x4 x5.(a_topic(x2) & exists e2 x7.(Actor(e2,x7) & v_watch(e2) & n_man(x7) & -(x7 = x3)) & n_man(x3) & n_man(x3) & while(e1,p1) & a_down(s1) & Manner(e1,s1) & Theme(e1,x6) & Actor(e1,x5) & v_walk(e1) & (x2 = x5) & of(x2,x4) & n_dog(x4) & for(x2,x1) & n_film(x2) & of(x2,x3))))