Beam focusers in the reactor of the Executor-class Star Dreadnought Terror The beam focusers acted as a part of the main reactor found within Executor-class Star Dreadnoughts. As part of an infiltration operation on the Executor-class Star Dreadnought Terror, Rebel pilots Rookie One together with Ru Murleen brought about the destruction of the beam focusers that resided in the vessel's reactor, which resulted in a critical meltdown and subsequent explosion.
