Mr. Laser Beam wrote:
Maybe the guard thought Sulu was going to try to talk his way into being allowed access to McCoy and so the guard decided to shut Sulu up before he could say anything.
Because he said, "Keeping you busy?" It looked more like the guard was being defensive because Sulu caught him yawning at his post.
To be honest it's probably "Little Hitler" syndrome. You know, like the Mall Guard or College Campus Security Officer who thinks that just because they got a uniform and a badge, they're gods in their own little world.
Newspapers are full of examples where people like this boss people around because in their field they have "power", the vocal few like them giving the general impression that all of them are like that, which explains why a lot of real Law Enforcement Officers usually treat guys doing this kind of job with contempt .