A) I certainly hope, for that character's sake, that they've got bucketloads of FPs to drop on their control roll.
B) With Inhuman Recovery, a moderate consequence clears at the speed of a mild consequence, which lasts for one full scene after healing begins. That would be, assumedly, the end of the scene following their nova-bomb.
C) If this nova-bomb, for whatever reason, fails to eliminate every remaining opponent in the scene, that practitioner is unlikely to last the scene without also taking, at least, a severe consequence.
D) Self-inflicted harm bypassing a toughness power is relatively easily justified, but even that could be said to simply overwhelm the power's protection, instead, given appropriate fluff. Having self-inflicted harm bypass a recovery power is less easily justified. The harm has already been done before the power has any effect, so there is no justification of 'it has to bypass the power for it to happen, it has to happen to get what you want, so it has to bypass'.