20 Things You Didn't Know About Star Trek III: The Search For Spock (1984)
9. The Most Difficult Scene To Direct Was Dr. McCoy's Speech To Spock In Sickbay
Leonard Nimoy pulled double duty on Star Trek III as both a director, and, at the end of the film, an actor as well. He appears as Spock in the scenes following his rapid ageing on Genesis, which meant that production had to take his on-screen time into account.
The most difficult scene to shoot, from Nimoy's point of view, was the one that featured Dr. McCoy speaking to an unconscious Spock in sickbay. For the scene, Nimoy had to appear, while unable to open his eyes or react.
This meant that he was blocked off from viewing Deforest Kelly's performance who, in Nimoy's words, was being driven demented by the little ticks that Nimoy was outputting. The director laughingly believed that Kelly felt he was attempting to direct him in code, with each blink signifying something else. Despite this, the scene plays out beautifully, leading into the final moments of the film and their parting, and reunion.