A medical professional in scrubs and a face mask is observing a surgery.
A chief surgeon observes a new doctor performing a surgery.
"Medical professionals" encompasses a vast range of jobs relating to healthcare, not just chief surgeons.
exists e1 s1 x1 x2 x3 x4 x5 x6.(Theme(e1,x6) & Actor(e1,x1) & v_observe(e1) & n_surgery(x6) & subset_of(x4,x1) & n_mask(x4) & of(x4,x5) & n_face(x5) & subset_of(x2,x1) & in(x2,x3) & n_scrub(x3) & n_professional(x2) & a_medical(s1) & Theme(s1,x2))
exists e2 e1 s1 x1 x2 x3 x4 x5.(Theme(e2,x3) & Actor(e2,x1) & v_observe(e2) & Theme(e1,x5) & Actor(e1,x4) & v_perform(e1) & n_surgery(x5) & (x3 = x4) & n_doctor(x3) & a_new(s1) & Theme(s1,x3) & n_surgeon(x1) & of(x1,x2) & n_chief(x2))