Kratos was fighting on Kronos' arm, right ?
Keep your hand on your elbow and move it towards your wrist..see how fast you can do that ? Do you think you can kill an ant on your arm with that motion ?
If you're kronos, and the ant is kratos....do you think he would have survived ? If Kronos could have done that, he would't have had to eat his grandson... 
Oh and Helios' head blinded him throughout the battle...







