"Mac is a double agent who has forgotten he's a double agent. He has switched sides so many times, he doesn't know who he's working for anymore. He is Indy's mate, but he can't help betraying him. (...) there's a bit of the Richard Burton character from the war thriller "Where Eagles Dare" in Mac." (Ray Winstone) "In 1957 a lot of popular literature was about spies, betrayasl, sneaking around. So the fun part about Mac is you never quite know whether to believe him or not. He tells lies throughout the movie to suit current circumstances. But he's charming, so we like him against our better insticts." (David Koepp).