you must shoot it in the head 
(ROOT (S (NP (PRP you)) (VP (MD must) (VP (VB shoot) (NP (PRP it)) (PP (IN in) (NP (DT the) (NN head)))))))
(ROOT (S (NP (PRP )) (VP (MD ) (VP (VB ) (NP (PRP )) (PP (IN ) (NP (DT ) (NN )))))))