His character (Sefton's business sidekick) was positively the least gimmicky one in the entire film. In the few moments he had dialogue the film seemed to transcend reality the best.

Now, to films and realism in general. Look. Most people believe that what was on film before about 1970 was totally unrealistic. Nothing could be further from the truth. Watching old 30's movies you would be shocked at themes (like 'Reefer Madness') and realism they had in films. Even back to the 20's films were kinda believable with on location filming and other details. Racism not always as big a deal in old films. When Rudolf Valentino played a sheik in 1921's 'The Sheik" no problem that he was too European to play one. His sheik was taken from two European visitors when he was a baby. Said so right in subtitles by Adolphe Menjou. (We could get into Italians in North Africa dating back to Roman times but no need to go there given film explanation!) More realism than we ever thought!