i can't stop thinking about what an incredible missed opportunity there was at the end of act 2 actually. so if you let gale blow himself up there's like one line from the dream guardian telling you to stop right? and then the narrator's all "oof. bad ending." and explains how destroying the brain in that way meant that all the tadpoles aren't in stasis anymore and the sword coast will soon get over run by mind flayers. it would make sense for the emperor to know that was a possibility and that's why the dream guardian doesn't want you to do it (and presumably also they would get blown up as well and they're not really a fan of that ofc).

now conveniently there's a whole ass conversation with your dream guardian right after the ketheric fight. so, larian, why doesn't the emperor go "hey good job you didn't let the wizard blow up that would have been the worst possible outcome"? and then explain what would have happened? like it sucks that as the player i can know that from seeing the alternate ending but gale never gets to learn the dumbshit thing mystra wanted him to sacrifice himself for. he does eventually (waaay at the end of his act 3 quest chain) get the idea that she was more worried about the crown than the brain but it could be so much juicier if he's already putting the pieces together at the end of act 2.