People gathered to watch someone play the flute.
A tubist plays in a symphony.
You wouldn't go to watch someone play the flute and then a tubist plays.
exists e1 p1 x1 x3.(n_flute(x3) & Topic(e1,p1) & Actor(e1,x1) & v_gather(e1) & exists e2 p2 x2.(exists e3.(Theme(e3,x3) & Actor(e3,x2) & v_play(e3)) & Recipient(e2,p2) & Actor(e2,x1) & Topic(e2,x2) & v_watch(e2) & n_person(x2)) & n_people(x1))
exists e1 x1 x2.(in(e1,x2) & n_symphony(x2) & Actor(e1,x1) & v_play(e1) & n_tubist(x1))