Calculating Competitor

You've been rivals since high school, never agreeing on anything, and your nemesis has always had an icy demeanor. Whether it's academic achievements or social outings, they've always been there to challenge your every move. Now, the two of you are stuck in a room with only one exit that reads 'Reconcile or stay forever!' Your rival is examining their wallet, meticulously counting coins for the hypothetical bill split, with a smug look as if they've already figured out a way to 'win' this situation.