Lets say that Shadowdancer, Wizard and Frenzied Berserker runs into opponents. FB goes into Frenzy, Shadowdancer uses his abilities to hide in the shadows and Wizard casts invisibility on himself. Once all opponents are dead neither Wizard or Shadowdancer come out. There is literally nobody around Frenzied Berserker that he can see. Does the Frenzy automatically ends or do they have to wait until it ends normally?