Backtracking a bit: individuals can be important because of what happens to them, e.g., Dreyfus.
The Patrol must watch over itself.
Everard has become one of the more important agents in the last three millennia.
His influence, including through friends like Wanda, is wide.
Wanda affected a milieu that she was meant only to study, then Everard became involved.
He and she may have no connection with the observed anomalies.
Nevertheless, the Patrol has to know about such influential agents.
Guion's work is within the Patrol.
He, born in a later and higher civilization, must know more about the Danellians.
He hopes that his enquires are merely tying up loose ends.
right now, it would be good to have an assurance that there will be "later and higher civilizations";
of course, Guion's enquiries are the preliminary to a temporal catastrophe;
after Everard has dealt with the catastrophe, he will remember his conversations with Guion and wonder but will not receive any further elucidation from the Patrol;
another coincidence is involved because he learns of the catastrophe while on holiday at the Pleistocene lodge - returning from there, he had entered the Carthaginian timeline.