Well it's really up to you how much (if any) damage your ship takes. The Entroper is a weapon that destabilizes molecular bonds, generally ripping matter apart at nearly the atomic level. The technology was originally designed as a mining tool (at a higher setting, the beam breaks all non-atomic bonds leaving nothing but pure elements in its wake), but was adapted into a handheld weapon shortly after its inception. It's on a lower setting right now, but is still powerful enough at this setting to break some of the molecular bonds in the breathable gases of the bar's atmosphere, causing a combustion reaction to occur around the beam of energy. The beam itself is almost colorless (translucent white), but it looks like a bolt of fire within the atmosphere because of the combustion reaction occurring around it's immediate proximity.
It only works on matter, however...so if you use an energy shield that's actually made of energy, even if it's too weak even to stop a Dracon blast, it will render the entropic beam harmless.