Anecdotal, but I got Charine once because I knew that he liked to recall when fighting in Hamsah. So I walk in and see him fighting some rager or somesuch. He words, I knife at the pit, he dies.
Could he have called Druktrar in Hamsah? Sure. But he was busy with other stuff; he calculated that the "cost" of doing it outweighed the benefit of going at this rager guy without having to putz around calling Druktrar on the off chance I was in the area (or would enter while he was fighting).
Stuff like that's going to happen. I tend to worry about the things I can't reasonably plan around, such as classes I can't see. (Also- unless your Scion is only going to play when he has his item, there will be times you won't be able to take advantage of Druktrar.)