OK, here are the order that things need to happen:
1) Gnorth needs to decide if he is going to take the OA on the bone naga. It's possible you may kill it, which would make Step 2 unnecessary. (Gnorth did indeed hit the 10% chance that he was going to kill it with his attack, Step 2 is no longer relevant).
2) Both Gnorth and Corilo need to roll saving throws vs. the lightning bolt the bone naga just cast (see the IC thread for notes, both of you are getting bonuses to the saves).
Lorenzo's save (DC12): [roll0]