It's fake.
It's suspicious that the portaled lasers were done like this.
LASER]=--------------------[PORTAL][WALL][PORTAL]--------------------[LASER RECIEVER]
It seems like that it's just an illusions and with some valve hammer editing, it's just two walls that when
portaled on both sides, spawns another laser at the other side, but it looks real as the inside of the portal "Links them up"