This is how we all learn. Dice sort of roll around, nobody's sure what's going on, and then someone dies horribly.
So, buying the initiative goes like so:
First, you spend a number of CP equal to the target's perception. In our case, 5. Now, this does mean that we've spend 14 so far, so we only have 2 dice left for the next exchange. (Better make it worth it.)
Then, we roll our WP (which is 4) against her Reflex (which is 7.)
She must then roll her Wit against our Reflex (7 against 6, Jesus Christ), BUT, each additional CP spent can raise this difficulty by 1, in our case to 8.
Yes, this is the most needlessly complicated part of the game. The long and short of it is:
Karl rolls 4 against 7.
Sheon rolls 7 against 8.
Whoever wins this roll is going to win the fight, barring ridiculous circumstances.