Anyone who's paid attention at all knows that the very front tube on Batman's belt is always the one he needs to reach. Sometimes it's an invisibility ray, sometimes it makes his feet turn into suction cups, and sometimes like here, it makes his car fly. But I don't think they're out of trouble yet. All he did is shoot his car at high speed towards the side of the other cliff. They're still tied up, and they're still about a second away from dying.