Just watch the following clip and then imagine how cool it would be if there was no safety-line, no tourists - only battered Indy running up this treacherous path escaping from his followers or maybe a 1960 helicopter from which he is shot at. He could slip at some point and almost falls to his death, but then barely safes himself by ataching his whip to a rail of the heli, then climbing up, beating the hell out of the baddies, pushing them outside and escaping with the heli.