Showing the players rifle sticking out of the wall:
http://imgur.com/bJqdYCA
Showing the same player semi-submerged in the roof:
http://imgur.com/GBvLofZ
This screenshot shows no visible player is on the roof:
http://imgur.com/5x6uaa6
This shot was taken immediately after and shows the player after he has 'risen' out of the roof:
http://imgur.com/Iofhzdc
I am 100% sure the player didn't just walk out from behind the cover as i clearly saw him rise out of the roof during the 'prone to crouch' animation.