But if a creature is surprised and no attack comes...what were they surprised by? How did they stop being surprised?
Order of Operations:
1 - Assassin: "I shoot my bow at the unaware guard!"
2 - DM: "Okay, the guard is surprised. Roll initiative."
3 - Init is rolled. Guard wins.
4 - DM: "Okay, the guard is not surprised anymore because of reasons. Your turn."
5 - Assassin: "Okay, I don't shoot the guard." / "...I ready an action to shoot the guard when she IS surprised."
6 - DM: "Uhh...okay, no combat happens, and the guard continues on its patrol, still unaware of you. What do you do?"
7 - Assassin: "I shoot my bow at the unaware guard!"
8 - ...etc?
Well the way I see it, everything is "KINDA" all happening at the same time (I mean they aren't waiting to take turns right?) so the init os just helping us emulate combat.
So once the assassin attacks from their ambush spot, that starts everything and I would not retrograde it. If the "monk" wins init, then they are doing the kung fu thing, if the monk doesn't win init, the assassin nailed them successfully.
No wonky involved.