 Ermey improvised insulting dialogue against a group of Royal Marines who were being considered for the part of background Marines, to demonstrate his ability to play the character, as well as to show how a drill instructor goes about breaking down the individuality of new recruits.Upon viewing the videotape of these sessions, Kubrick gave Ermey the role, realizing he "was a genius for this part".Kubrick also incorporated the 250-page transcript of Ermey's rants into the script.