Steve McQueen would have successfully jumped the barbed wire, rode to Berchtesgaden, snuck up and smoked all three, plus Bormann, and been out of there.
But the real question is, since the photo predates McQueen's masterpiece Bullitt, would he have arrived at the location on two wheels in his '68 Mustang GT?
No, on the motorcycle he stole when he broke out of the prison camp in "The Great Escape". Hello, he's already in Germany. Why escape, go to the U.S., start a successful business, and THEN travel back to Germany and wack Hitler and three members of his inner circle?