They initiated their cockpit takeover within 30 minutes of takeoff.
( They ( ( ( initiated ( their ( cockpit takeover ) ) ) ( within ( ( 30 minutes ) ( of takeoff ) ) ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (VBD initiated) (NP (PRP$ their) (NN cockpit) (NN takeover)) (PP (IN within) (NP (NP (CD 30) (NNS minutes)) (PP (IN of) (NP (NN takeoff)))))) (. .)))
They couldn't muster the courage to initiate the cockpit takeover. 
( They ( ( ( could n't ) ( muster ( the ( courage ( to ( initiate ( the ( cockpit takeover ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (MD could) (RB n't) (VP (VB muster) (NP (DT the) (NN courage) (S (VP (TO to) (VP (VB initiate) (NP (DT the) (NN cockpit) (NN takeover)))))))) (. .)))