Wonder if they ever heard the report of the rifle?
If they did, they probably said, "what was thaaaaaa......"
The bullet got there in 10 seconds. In 10 seconds, sound would only go 2.13 miles, not the full 2.2 miles. So the bullet beats sound in this case.
Since we don't know the conditions of the shot such as wind speed, altitude, etc.. we can assume optimum conditions and set a baseline.
The speed of sound is 1,088fps (feet per second)
The shot was 11,316 feet.
It would've taken approx. 10.4 seconds for the shot to be heard.
A 50 caliber bullet travels @ 3,000fps.
The bullet arrived at its target destination in @ 3.8 seconds.
The bastard never knew what hit him, and that's a shame. I want the bastard to have said "what's that? OH NO!" before getting his brains splattered all over the place.