Epic pool for a Water/Rad Corruptor?

[Snowbluff]

Hello. I've been playing my first corruptor and had landed on Water/Rad for the build. However, I didn't figure I would level this high so I didn't have a plan for their epic pool.

I was looking at maybe Electricity mastery for another disorient, and the armor seems good. Dark also seems like it could be cool with Oppressive Gloom.

[Astralock]

Depending on the build, I always go with either Mace Mastery for Scorpion Shield, or Mu Mastery for Charged Armor.