Jarrah, like Atta earlier, may have inadvertently broadcast the message because he did not know how to operate the radio and the intercom.
( Jarrah ( , ( ( like ( Atta earlier ) ) ( , ( ( may ( have ( inadvertently ( ( broadcast ( the message ) ) ( because ( he ( ( did not ) ( know ( how ( to ( operate ( ( ( the radio ) and ) ( the intercom ) ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) ) )
(ROOT (S (NP (NNP Jarrah)) (, ,) (PP (IN like) (ADVP (NP (NNP Atta)) (RBR earlier))) (, ,) (VP (MD may) (VP (VB have) (VP (ADVP (RB inadvertently)) (VBN broadcast) (NP (DT the) (NN message)) (SBAR (IN because) (S (NP (PRP he)) (VP (VBD did) (RB not) (VP (VB know) (SBAR (WHADVP (WRB how)) (S (VP (TO to) (VP (VB operate) (NP (NP (DT the) (NN radio)) (CC and) (NP (DT the) (NN intercom)))))))))))))) (. .)))
Jarrah used the radio rather than the intercom.
( Jarrah ( ( used ( ( ( the radio ) ( rather than ) ) ( the intercom ) ) ) . ) )
(ROOT (S (NP (NNP Jarrah)) (VP (VBD used) (NP (NP (DT the) (NN radio)) (CONJP (RB rather) (IN than)) (NP (DT the) (NN intercom)))) (. .)))