Because I don't think I totally understand the question, and I don't really know the answer either. Only thing I can say is it's probably a random factor to make the game less repetitive.
I'll try to explain it better. We'll use Kingdom Hearts II and Donald for the example.
When Donald supports himself (healing himself or using an item, such as an ether, on himself), there are two things he can say: "Okay!" or "Yeah!"
If he gets attacked and falls into low health, he'll say "Heeeeeelp!" If he gets attacked with a knock-back attack, he won't be able to heal right away because he needs to finish falling and then get up. However, if he just gets hit with an attack that does *not* cause knock-back, he won't have to recover and can heal right away. For some reason, if the latter happens, he won't say "Okay!" or "Yeah!" and will silently support himself, like the "Heeeeeelp!" audio clip is still in effect even though he's done saying it.
The other one is that some battle cries can override others while some can't. Let's say, again, that Donald falls into low health from a knock-back attack -- "Heeeeeelp!" He uses Donald Cure and starts saying "Yeah!" when Goofy uses a potion on him -- "Donald!" Instead of Donald finishing his "Yeah!" you'll hear something like this: "Ye-- Thank you!"
Now, to use an example of battles cries not overriding each other, again, let's say Donald falls into low health -- "Heeeeeelp!" -- and Goofy uses a potion on him while he's still crying for help -- "Donald!" Donald will be still be saying "Heeeeeelp!" and won't say "Thank you!" because "Thank you!" cannot override "Heeeeeelp!" However, obviously if he were saying "Thank you!" from being given an ether and then fell into low health, then "Heeeeeelp!" *would* override the former. "Thank-- Heeeeeelp!"
Hope that made more sense. And if it does, check out the thread again and see the videos.
I've got a lot going on right now, and I just forgot.
Sounds like different battle cries have priority. Obviously you want the damaging ones to override, because the character is being hurt. It would sound silly if someone was talking calmly while getting beat up. Similarly if someone was about to get hit by a train, but was pulled away at the last second, they wouldn't stop screaming to immediately thank the person, because they would still be in that moment of shock. The programmers could have had the characters say "thank you" later on, but battles move so quickly, it could become a confusing mess.
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