Two people working in mud.
A person sitting in a lobby.
There should only be one person or two people. People can't be sitting in a lobby while they are working in the mud.
exists e1 x1 x2 x3.(a_topic(x1) & in(e1,x3) & n_mud(x3) & Actor(e1,x2) & v_work(e1) & (x1 = x2) & n_people(x1) & card_eq_2(x1))
exists e1 x1 x2 x3.(a_topic(x1) & in(e1,x3) & n_lobby(x3) & Actor(e1,x2) & v_sit(e1) & (x1 = x2) & n_person(x1))