Yoshida (and Y'shtola's dialog after the fight) does imply that Emet is the one that fixed WoL's aetherial imbalance by counteracting all the Lightwarden's Light, so it's not unreasonable to think that the same happened in reverse. However I do think that when we consider his actions before the trial, the question of his tempering and what effect that actually had on him isn't so easily answered.