(S (S (ADVP (RB There)) (COMMA ,) (S (BASENP (PRP he)) (VP (VP (VP (VBD opened) (BASENP (NN fire))) (PP (IN upon) (BASENP (JJR more) (NNP USAF) (NNS airmen)))) (COMMA ,) (S (VP (VP (VBG killing) (BASENP (DT a) (NN second))) (CC and) (VP (VBG injuring) (BASENP (NN two) (NNS others)))))))) (PERIOD .))