If not for those meddeling patriots alerting a cop that there was a shooter on that roof and that cop alerting that sniper and that sniper blowing yearicks brains out Yearick would have been snuck out of there and Crooks would have been swatted within hours.
Think that over and put the puzzle pieces together.
I assume that a second gunman wouldn't have used a 5.56, my guess is something like a 6mm Creedmore or Dasher, a much better precision load. Even the vaunted 5.56 77gr SMK, Mk 262 isn't what I consider a precision load.