When Joe's stuntman vaults down the hospital staircase to tackle one of his pursuers, his hat falls off in the process. He then stands up, still without his hat on, and gets ready to punch the man. The camera then switches to a closeup shot of Joe with a hat on punching the man. Then the camera switches back to the wide shot again where the stuntman picks up his hat and puts it on and then runs up the stairs.
When Joe Mannix and Dr. Considine are trying to board a plane to escape from the repressive country where Considine has treated Victor Lucas for his heart condition, Considine appears to have shaved most of his head to pose as a Buddhist monk. In a closeup, however, when Colicos turns his head, the edge of a tight-fitting, sheer membrane can be seen stretching at his neck, revealing that Colicos wore this over his own hair so that it would look like he shaved his hair without actually having to do so.
When Joe and the doctor slip into the hospital, a TV over the entrance desk is seen showing the wanted men's photos. When the set is switched off, it reveals we've been seeing a superimposure, and the set is only a hollow frame, with nothing inside. By WesternOne.
The Bell 47G helicopter used to retrieve the pacemaker has an American registration (N8597F) which would be unlikely in the foreign country used in the plot. The range of this aircraft would not permit flight from the USA to this country.