 To guard against leaks that had prefigured Spock 's death during production of The Wrath of Khan , Paramount took precautions to secure the sets . Set designer Cameron Birnie noted that the production 's security was highly unusual ; sets were built out of sequence and the crew given only as many pages as they needed to fabricate each locale . Security guards checked the picture identification cards of production staff . Any mention of the production was removed from stationery and documents , and " Trois " ( three , in French ) was written as a code word . Offices and workshops were bereft of identifying signage , with doors double @-@ locked for extra protection . The Search for Spock 's scripts were chemically treated so that copies could be traced to the original ; as a further canary trap , subtle changes in wording distinguished each copy . Nimoy 's name never appeared on call sheets , and Spock was referred to in the script as " Nacluv " ( Vulcan spelled backwards ) . Despite the precautions , word of the Enterprise 's destruction leaked out before the film 's release . 
