When testing for max damage single hits with Inner Death i found a bug where Inner Death does not get the 30% Shock Damage from Lightning Strikes when Turning Wheel is skilled. Instead the Damage just adds the fire Damage form Turning Wheel see Combatlog of Screenshot:

 

The first half shows a hit with Inner Death (Only Fire Damage is added) the second hit is a normal attack (fire and lightning damage from Turning Wheel and lightning strike is added)

 

 

 

I think this not bug, lightning Strikes work only for attacks, not spells. Inner death is considered a on-touch spell, like jolting touch.