Given the comments about the "command ejection" configuration I have been researching whether there was any previous incident where the front seat occupant of a Hawk was the pilot and ejected, and a rear seat occupant, who was not a pilot, remained with the aircraft.
I have found an example and very fortunately both survived. No explanation is given as to why the rear seat occupant did not eject.
The accident happened as the Hawk was landing in 1982.
The rear seat occupant was a flight test observer.
https://aviation-safety.net/wikibase/wiki.php?id=55500