Well, all the credits go to a friend of mine ([ Ссылка ] let him become as famous as Rebecca Black). He just mentioned that there's an easteregg in a vent that's guarded by a turret and I kept looking for it in my second playthrough: Here it is!
extra tags:
Portal Choir Turret Easter Egg Video Game Steam Puzzle Ego Shooter Funny Melody Orchestra howto "video game" engine source aperture science cave johnson "turret singing" sing song singing "Portal 2 Turret" "Portal 2" "Singing Turrets"
![](https://i.ytimg.com/vi/fbzUT-99w88/maxresdefault.jpg)