Viewers were stunned when 007's controller, played in seven Bond movies by Dame Judi Dench, died at the end of the 2012 installment following a confrontation with the film's villain.
Mendes admits he was wary of the consequences of taking such a dramatic step while directing his debut Bond movie, but insists it could have been worse as he toyed with the idea of killing off Bond instead.
The American Beauty director tells British newspaper The Guardian, "Everyone in the audience knows that Bond's not going to die. But you have to make people believe that there's a danger he will... Ha! You can't kill him; let's kill her instead! I thought I was going to get so much s**t for that. But you know you shock people into rediscovering their first acquaintance with the characters..."