James Doohan's accent a 'Scotty' try-out?
It always struck me that James Doohan's faux Scottish accent in his one line in this film was sort of a dry run for the role of Scotty -- not intentionally, of course, but maybe it helped put him in the right frame of mind. (Those who still haven't found him, he's about five minutes into the film, entering the room where Garner and Alan Napier are discussing the D-Day invasion -- he stands in the doorway and delivers his one line.)
The plot of the movie must have hit him close to home because in real life Doohan was wounded in the Normandy invasion. The middle finger of his right hand was shot off, and if you watch his many performances you will see that he always tries to cover the hand a little, folding his fingers up, holding the hand slightly behind him, using his left hand as much as possible, etc. (as he does here in his brief scene). Only occasionally do you notice he's missing a finger.
36 HOURS is notable also for the three performers who made it big on TV soon after this movie: James Doohan in "Star Trek", John Banner in "Hogan's Heroes", Alan Napier in "Batman". Good they finally got the recognition they deserved after so many years of great performances in small movie roles.