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 think Yearick got the job because he was supposed to be a one shot guy and then a good run away guy. In his company he'd have to know his friendlies would potentially kill him if it went south. I see him as supposed to be a pro worth trying to keep that was heavily invested in.