I can't shake the feeling that this was actually a setup by clever crown prince to see what she's capable of, except he didn't think knives would be part of the equation and he has to intervene mostly because it's the right thing to help someone at a disadvantage. He seems hypervigilant so even if their paths crossing was coincidence, I doubt he wouldn't have noticed her tailing him (no matter how good she is, crown princes tend to be very familiar with assassins and he already has his hackles up re: Aideen). It feels too soon for him to find out tho. Unless that's actually a plot point that changes the future she's lived.