Destroy turrets in sewers was a mission in Jak II. Krew had some other job for Jak this time and promised him a weapon upgrade in return. Jak had to go into the Haven sewers and destroy the sentry guns Baron Praxis had installed as security devices, so Krew could continue his 'smuggling'. The PlayStation 3 and Vita versions of this mission are related to a trophy named "Turrets Syndrome", completing this mission will reward you with a bronze trophy.