My player's character, a 4th level wild magic sorcerer, cast magic missile as a 2nd level spell after using Tides of Chaos. Since she had used Tides of Chaos, I had her roll on the Wild Magic Surge table to recharge it. She rolled a 07, the dreaded self-fireball. As her character had only 4HP left, and failed his Dexterity saving throw, he instantly died a spectacular death.
In retrospect, could she have potentially saved her character from instant death by using Tides of Chaos again, on the Dexterity saving throw? My understanding of the rules was that Tides of Chaos recharges after the wild magic surge occurs. However, I recently noticed it says that you get it back after rolling on the wild magic surge table, which is arguably complete before the fireball goes off.
Is there any clear rule about this, or is it up to the DM's judgment?