When Carissa first arrived at the Worldwound they had an introductory briefing in which it was explained to them that half of them would serve out their ten years and half would die.
She doesn't know if that statistic is the same as the one in the census records, or the same as the betting odds anyone would give, but she took it as what it was: a thing to think about, if you were considering being incompetent, or lazy, or stupid, or annoying. You'd die, if you did that. You might die even if you didn't. Cheliax has the greatest military in the world but this is because they do not tolerate weakness, not a reason to expect to get away with it.
She took the project of not dying very seriously; she expected to be nearly useless to Hell, if she died this young. She demonstrated prowess at magic item enchanting to keep herself generally off the front lines. She figured out who it was important to get to like you and was diligent and convenient to them. She didn't drink, and didn't waste her money she was saving for a headband, and refined her spells until she could fit more on the scaffold and got some for personal use.
And she still died, apparently.
She is being less careful than that, right now. She isn't sure she has a choice. Everyone knows how to be a careful wizard at the Worldwound, it's an established kind of thing to be. You try to be valuable off the front lines and you try to be less annoying to your superiors than your replacement would be and you obey orders and you don't make any mistakes. And here she has no one to obey and she is a provocation by her very existence and she doesn't even know what counts as a mistake. It's terrifying.
But, in her soul -- which she apparently no longer possesses -- in the hole in her where a soul should go - she is a wizard, and wizards really do all want phenomenal cosmic power. You can feel it at your fingertips. You always know it could be yours, if you live long enough.
She would like to try to pick up channeling all of the other kinds of aspected mana, and then she'd like to invent some spells with those and cast them repeatedly and burn herself for taking too long, and then she'd like to see if she can pick up any of the Tier-2s, and then she'd like to read through all the books and see if there's anything more about things Summoned Heroes always realize or always do, things that'd explain why they always leave, things that'd explain how they'd leave a world like this instead of just ascending like a normal fucking person. And then she'd like to do more magic until she's about to collapse from exhaustion, until the Rope Trick runs out and lets her crash, bloodied, to the inn floor.