Friendly Fire
Uncommon34.3%ObjectiveOptional
Knock down a turret with another turret.
Pick up one turret and use it to bowl over another. Easiest in a turret-heavy room like Test Chamber 16 - grab a turret, carry it, and swing or walk it into one of its friends so the turret you're holding knocks the other flat. It has to be the held turret doing the knocking. Quick and optional.