A person did a side flip while water boarding.
A person did a flip while on the water.
water boarding implies that one is on the water.
exists e1 x1 x2 x3 x4 x5.(while(e1,x4) & n_boarding(x4) & of(x4,x5) & n_water(x5) & Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_flip(x2) & of(x2,x3) & n_side(x3) & n_person(x1))
exists e1 x1 x2 x3.(n_water(x3) & on(e1,x3) & r_while(e1) & Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_flip(x2) & n_person(x1))