D&D 5E Ghosts of Dragonspear Castle Pointers

[Hutchimus Prime]

I'll be running the last of the four Ghosts of Dragonspear Castle adventures this weekend (spoilers on). I was wondering if anyone who has run it has come up with a way of foreshadowing the workaround to Isteval sacrificing himself at the end? I know the adventure itself suggests something, but I'm worried my PCs won't pick up on it and I'd like to give them every chance to.

 

[Mirtek]

I'll be running the last of the four Ghosts of Dragonspear Castle adventures this weekend (spoilers on). I was wondering if anyone who has run it has come up with a way of foreshadowing the workaround to Isteval sacrificing himself at the end? I know the adventure itself suggests something, but I'm worried my PCs won't pick up on it and I'd like to give them every chance to.

I wouldn't give them too many hints. Figuring it out should be an accomplishment and at the end of the day the occasional defeats makes the victories all the sweeter.