I just dont understand why the MC is such a moron, revealing his skills to everyone. Especially skills that ought to be kept secret.
This plot is so forced. He could have just outright refused to reveal his relationship to Olivia rather than tell some lame lie. "It's none of your business", "i have no obligation to answer that question" etc. are the right answers to some asshole that points his sword at you and demands to know your secrets.
Since he was asked to help, and is a volunteer the right answer is "ah, so this is how you treat uninvolved foreigners you've asked for help? Then fuck off, im going home. I have no obligation to put my life on the line for your city"