Oh crap... I think I might have created a massive mishap. Nobody tested the Priscilla mode enough so I fear that I haven't removed the invincibility of the one in that fight. I can't fix that since its currently at judging phase. This is a massive oversight. I apologize for this. The only way to circumvent this is to either defeat Lucius before the minions are defeated, defeat Lucius to 50% while the minions are alive or try to switch to Reid mode... which is a harder point. Or if you're playing this on 1.1 with Reid Mode on it, try the 1.0 version, that basically has all the bells and whistles fixed.
I'll make a 1.20 addressing this at a later time post jam. My sincerest apologies for this mishap.