Sydney Pollack's Three Days of the Condor has always been one of my favourite movies, not only in regards to the spy movie genre but in general. I have known for a long time that the novel on which the film is based presented many differences with the movie (beginning with the title - Six Days of the Condor) and I have always been curious about founding them out.
Warning: spoilers ahead
A few days ago I finally started reading the book and I've reached the part in which Condor (played by Robert Redford in the movie), after finding out that all of his CIA colleagues have been slaughtered in their office while he was out getting lunch, runs to a public phone and dials the "panic" number. I clearly remembered the scene I saw in the movie many times since I was a kid. After receiving instructions from the experienced agent on the other end of the line, Condor is told to:
"Walk away from the phone; don't hang it up"
This can be read at page 30 of the final draft of the original screenplay and can also be seen in the clip below at 15 minutes circa (I couldn't find the scene I was looking for in english):
In the book instead, Condor is told to:
"hang up now, and remember, don't lose your head"
The screenplay of the movie was written by Lorenzo Semple Jr. and David Rayfiel. I'm not aware if James Grady, the author of the novel, participated to it or if he was consulted at all. As anticipated, many changes were made to the original plot, but I was wondering about this particular change. Why Condor would have had to go away from the phone without hanging it?