 Martin Sheen (qv) was actually drunk in the scene where Willard is  drunk alone in his hotel room. All of Sheens actions in that scene  were a result of his real intoxication. When Sheen punched the  mirror (which was real glass), he really did cut his hand as shown  in the film. While drunk, Sheen also began sobbing and tried to  attack Francis Ford Coppola (qv).