Sorry, I don't have any inside info. All I've done is look at the man's record. There are two main career tracks in the NYPD for the ambitious; "boss" and "detective". I may be wrong, but I don't think in over 150 years has there ever been an NYPD commissioner whose previous department rank was 3d grade detective. The guy had a good relationship with Giuliani and made the most of it. I can tell you with certainty that there were others that were better qualified to hold the post that he had on that fateful day.
Thanks for the "insight" info, nevertheless. :o)