Toward the beginning of the move, when Lex is climbing the ice wall and she gets the cell phone call, they show a far shot, where you can clearly see the ledge above her with nothing on it. When she gets the call and gets to the top less than one minute later the helicopter is already at the top of the ledge, and she is surprised it is there. If the helicopter would've flown to the ledge while she was on the phone don't you think she would've noticed the loud sound of it? The helicopter should've been on the ledge in the long shot.