 What did Charles probably realize at the end?
There should be an epitaph for every man, big or little, but a really grand and special one for Loner Charlie. New York lay quietly below him. It was the hour of indecision when day has not quite made up its mind to leave and night has not yet attacked in force. Within a year it was obvious to everyone that man was the only animal left on earth. And now.... "I've got to find out," Charles told himself. And again at the age of 10 each child returned to the Bureau for a recheck. Charles activated the switches that would flash a schematic map of New York on the screen. Charles was by himself, the last person alive in all of New York City.
 He was the last person because of his last name
 He could have stopped the plague  There were more people alive that he hadn't found  There was an alien on the Empire State Building  He was the last person because of his last name