So I’m no expert, but here’s the process I’d go through:
The consequences depend on what’s been set up in the fiction I think. You have choices depending on what makes sense and what the result of the roll is.
So in this case, the archer’s hidden; they’re probably in a Controlled or Risky position. If they’re in Controlled, they’ve got the chance to back down from their action (maybe they decide there’s no good time to shoot, and need to take a different approach, like switch to jumping onto their opponent and sticking a knife in them, maybe rolling Prowl to do it?), or continue.
For 4-5, could be reduced effect (glancing or non-lethal if they were going for lethal), consequence (the target fires in return so inflict level 2 harm, or that’s the last of their ammo/the bowstring snaps), worse position (going to Risky or Desperate as they’re found out, maybe the target goes down but their buddy runs over to your archer’s cover). The cover affects what makes sense here; maybe you decide that other targets get scared off instead of trying to find the archer and they run off with your objective, or that the worse position makes more sense than inflicting harm, or that the archer’s still in the same position as before when they want to sneak away instead of having to fight their way out).
For 1-3, similar deal, but no benefit (the archer didn’t actually get what they wanted AND bad things happen).