Gosh, I can think of an old analogy that fits this one!

I'd rather be judged by 12 than carried by 6!

The Grand Jury will deliberate with the 1st shot not the 2nd

Which one of the bad guys get shot 1st, 2nd or 3rd is all situation dependent

If the "double tap" is needed....take it!

Did the bad guys have weapons? I'd certainly shoot the guy with the gun pointed at me first!