Jon ran as the tunnel collapsed behind him.
( Jon ( ( ran ( as ( ( the tunnel ) ( collapsed ( behind him ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Jon)) (VP (VBD ran) (SBAR (IN as) (S (NP (DT the) (NN tunnel)) (VP (VBD collapsed) (PP (IN behind) (NP (PRP him))))))) (. .)))
The tunnel remained intact.
( ( The tunnel ) ( ( remained intact ) . ) )
(ROOT (S (NP (DT The) (NN tunnel)) (VP (VBD remained) (ADJP (JJ intact))) (. .)))