You know that people have done tests and proved that are only 3 rares UP each time, and every time you kill 1 rare, another one respawns.
Now there is a theory that when you keep killing rares all over the continent, you can lower the Respawn Time from TLPD/Viragosa to 4h-6h making it easier to get.
So if you keep killing all the rares, you can get it faster. That's what Josefina did, I guess. While she kept killing the rares all over the continent, she killed * Loque'nahak a few times.
Sorry, I couldn't resist either.