Season 1, Fire and Water
Omoroca left her lover to go teach the humans that the goa'uld weren't gods. I was thinking that this parallels a Peace Corps volunteer going into a war zone to help the natives. She knowingly went into incredible danger because it was the "right thing to do."
Nem would have tried to stop her. Then he waited for thousands upon thousands of years, sure that she would return if she could. I think he knew she must be dead, but finally needed closure. He needed to confirm her loss. Nem missed her for nearly our entire remembered history.
Out of sheer disinterested altruism, she helped free our entire species.
The challenge was for the US Memorial Day, to remember those who fell protecting innocents and civilians.