(S (S (BASENP (NNS Police)) (VP (PP (IN at) (BASENP (NN one) (NN point))) (VP (VP (VBD described) (BASENP (DT the) (NN raid))) (PP (IN as) (S (VP (VBG entering) (NP (DT a) (QT (DQL ``) (BASENP (JJ challenging) (NN phase)) (DQR ''))))))))) (PERIOD .))