So while your characters might be enjoying their endless day, it doesn't mean you want to have the experience recreated for you when "exploring" the Regulus Mines area.
As it's a trial and error dungeon of selecting the right route and the wrong route can take you back to several minutes of retracing steps with absolutely nothing happening, save yourself the tedium and headaches and just use this simple guide.

• Turn
  
• Go straight
  
• Turn again

You've now hit the boss of the dungeon and saved yourself a potential hour of missteps with the dungeon that is bigger than it actually is.

That's it.