The experience bomb is being explained as the result of learning something particulary useful in a fight, e.g. a new trick which you hadn't thought of before.
Where it says "a new trick which you hadn't thought of before" it doesn't specify you the player or you the character. I thought it was something I had to do.
In most role playing games the character learns something, not the player !
The first time playing it I wouldn't know about Marked Ones or Divine Ones, about the Sword of Lies or the Black Ring. I learned about these things as the character does. Playing it again I wouldn't be able to tell Zandelor what happened to the Sword of Lies until the character looks and sees it for himself. However in a fight the character doesn't decide on his own to use lightning against creatures with low resistance to it. That's something the player has to learn and the character doesn't.