looked to me like he shot him cleanly then cs:go decided to yank the bullet left through the wall first in an attempt to make it miss. thats how i miss my shots, cuz cs:go. crosshair right on the guy y u no hit.
It wasn't a lucky shot. There's always an explanation. You probably took the red pill and the matrix of GO altered the vectors of the map in your favor. You might be the One of CS:GO.