Replying to myself, how sad...

I might have been a bit unclear there. What I neglected to add was:

If the shot occurs in the middle of a combat, then my advice can just
be taken as-is.

If the shot is an assassination attempt, play it as a nemesis
conflict, with the shooter getting in position, avoiding guards,
waiting patiently, aiming, and then shooting as the coup de grace. And
the other players don't have to do nothing, they can be causing
distractions, stealing itineraries, and tying up the enemy resources.
All while the nemesis marshals his security forces to round up
suspicious types, search rooftops etc.