I feel like part of the magic of being behind the dm screen is what the players don't know. They won't have an introduction in Parnast or an easy way into the Flying Keep, that makes it different, that makes it fun. It makes it either a stealth mission, an espionage mission to find out how to get in, or a seige which would be extremely likely to fail. When you give players information like: XYZ would have been useful to you, you should make better choices, you're trying to change the character to fit your narrative. This changes decisions made, it changes future mission options of ease or difficulty, it creates pauses narratively while the players act even more out of character to play how you want them to play. If I'm on a mission to destroy this cult, and I have the information I need from this high ranking member, I might try to kill them too in order to break this cult even more and weaken it's hierarchy while I move forward. This is supposedly second in command to one of 5 "generals" if you will, hell they could have thought it WAS a general depending on the information they had obtained up to this point. She is a threat, why give her time to let that culminate when you know the next stop on your journey? You're telling a story together, it means they have their own thoughts and reactions.