Ether Rumia already ate Aya, or Aya is too fast to catch and eat. I doubt Rumia would care if Okuu were radioactive, even if the radiation did harm her.
StriderTuna said: Like that'd happen.... since for one.. Okuu's radioactive, and second, final boss calibur (on that chart, Okku would be at least an A)
Rumia could probably beat most Touhou characters if(A.) she put her arms down and/or(B.) took off her amulet.