i think that when you go up the stairs there is a big tower that i think got a electiflyed by the thunder in the sky and then a blast of thunder got shock off the tower to hit the airplane your in in the cutscene and if you looked at the shi no numa story then you will know the person who got the zombies back to life and he was the one who shot the thunder to get you down to kill all of the marines one by one add me psn ViperousWolf for more info