After the Story Mission titled "Dog Soldier", Jason jokingly requests to be killed if he starts showing symptoms of rabies. The quest-giver says "I'll buy a shotgun," and Jason laughs. He's probably seen the film... until he asks why you are laughing. Turns out he was serious.
The last "final move" unlocked under the "merciful" category hints it involves dancing, and its description states "Admit it, you know all the moves." The move has the player free the hostage, and the two perform "The Macarena" together.
The last "final move" unlocked under "violence" has the player pummel the hostage, before the player bends down and "teabags" the hostage.
'Ride of the Valkyries' is of course a famous and revered piece of classical music in spite of it's use in Apocalypse Now but given the thematic similarities between the two pieces of work it's safe to assume it's a reference to the film.