Anybody that knows rifles should know that not even a .308 will stay on its intended path going through a tempered glass window. This tells me this guy is not the average military type by using a .223. Not to start flames about the weekness of the .223 (as I own A Remington .223 and also an AR-15)both are accurate rifles, but shooting through windows shows his unprofessionalism (not really a word but you get the point)
The window was his first and only miss, he may be learning as he goes.
Anyway, the shooting is the easy part of his task, finding good shooting spots and escape routes is the more important and difficult skill.