At one point in the Jerusalem bazaar, from what I've heard, you can see Fawaz's (the meat seller) daughter appear taking a shower in the window. If you get too close, Fawaz will kill you (after Merlin shouts a single warning, like usual).

How do you get this to trigger? I've tried reentering the screen numerous times, as well as waiting around for about ten minutes, but so far I've gotten the daughter to show up.

Yep. You just have to reenter the screen often enough. The probability of it occurring isn't actually all that small.