I'm just saying, from a stats type perspective.
Either they often find guys with guns in buildings or areas they clear and missed this building and area, and therefore missed a gun.
Or there were a lot more than a chink or two in the armor and it was easy pickings.
But the guy with the rifle being in the right spot at the right time is what we have here.
Is there another option?
Shooter was seen on roof with gun by people 6-deep+ drinking Rolling Rock two minutes before he fired.
Was this a SNL skit?