Perhaps the terrorists stabbed the flight attendants to get a cockpit key, to force one of them to open the cockpit door, or to lure the captain or first officer out of the cockpit.
( Perhaps ( ( the terrorists ) ( ( ( stabbed ( the ( flight attendants ) ) ) ( ( ( ( ( ( to ( get ( a ( cockpit key ) ) ) ) , ) ( to ( ( force ( one ( of them ) ) ) ( to ( open ( the ( cockpit door ) ) ) ) ) ) ) , ) or ) ( to ( ( ( lure ( the ( captain ( or ( first officer ) ) ) ) ) out ) ( of ( the cockpit ) ) ) ) ) ) . ) ) )
(ROOT (S (ADVP (RB Perhaps)) (NP (DT the) (NNS terrorists)) (VP (VBD stabbed) (NP (DT the) (NN flight) (NNS attendants)) (S (VP (VP (TO to) (VP (VB get) (NP (DT a) (NN cockpit) (NN key)))) (, ,) (VP (TO to) (VP (VB force) (NP (NP (CD one)) (PP (IN of) (NP (PRP them)))) (S (VP (TO to) (VP (VB open) (NP (DT the) (NN cockpit) (NN door))))))) (, ,) (CC or) (VP (TO to) (VP (VB lure) (NP (DT the) (NN captain) (CC or) (JJ first) (NN officer)) (PRT (RP out)) (PP (IN of) (NP (DT the) (NN cockpit)))))))) (. .)))
It has not been proven that he terrorists stabbed the flight attendants or that they had any nefarious intent.
( It ( ( ( has not ) ( been ( proven ( ( ( that ( ( he terrorists ) ( stabbed ( the ( flight attendants ) ) ) ) ) or ) ( that ( they ( had ( any ( nefarious intent ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ has) (RB not) (VP (VBN been) (VP (VBN proven) (SBAR (SBAR (IN that) (S (NP (PRP he) (NNS terrorists)) (VP (VBD stabbed) (NP (DT the) (NN flight) (NNS attendants))))) (CC or) (SBAR (IN that) (S (NP (PRP they)) (VP (VBD had) (NP (DT any) (JJ nefarious) (NN intent))))))))) (. .)))