In the frequently used stock footage of McGarrett running down the palace steps to his vehicle, he sometimes seemed to changed clothes on his way to his destination. In this show, he left in a light blue suit and arrived at the site of the first murder wearing a dark blue suit with a red tie.
McGarrett has the radio dispatcher transmit an audio to open the garage door. Garage door openers work on a radio frequency and would not have responded to an audio tone over the car radio's speaker. Garage door openers of this vintage only had a limited number of frequencies that were often triggered by aircraft radios broadcasting nearby. Had McGarrett used a transmitter that he might have had in his car, there would have been a 1 in 4 chance it would have really worked.
Danny says Jack the Ripper claimed at least 18 victims. Scotland Yard thought the figure might be 11, only the so-called "canonical five" are included in most lists.
After Charlie has killed Aunt Martha, he carefully wipes her cane of his fingerprints, but does not bother to wipe his prints off of Aunt Martha's watch, which he has just set ahead and smashed.