I got quite pissed at that first attempt to defeat what was then the Elder Brain because I just kept rolling low every time. Burnt through all of my inspiration and never rolled above about 11. But then when it was DC 30, DC 99 I realised I wasn't supposed to win there, and the second attempt is way better as a whole experience. I'm not sure how I think they should have implemented it though. Because by putting the roll up it makes it look like you do need to succeed, which is what your character should be thinking. Maybe if they just made it so that particular roll never comes up as a 20. Would anyone even notice?
I think this was intended as a plot twist. You think you can win, then you can't, then even if you are technically failed you are saved anyway. Just a bit of a roller-coaster for the player)
