Ken, it seems that Ambrose is becoming a stone cold killer like Arthur.
Of my two pilots, Alvin is a lot harder than Ambrose. The death of Rex Warneford (who you didn't have since you run without HAs) and his talk with Godolphin on his day off affected him, but not so much that he's quite ready to start shooting. His demons actually keep that in check to some extent.
Ambrose, on the other hand, was more naive and idealistic about the war, and since 3 Sqdn has had light casualties, he hadn't been personally touched. The death of his long-time observer combined with the arrival of Hubert Harvey-Kelly (another HA - interesting dude) was enough to change him profoundly. There's still some of the old Ambrose in there, but now he's a man with a mission.