Despite the severe corruption of the Eye of Truth, its ability to hear the voices of a hidden entity at any moment, and the risk of encountering uncontrollable negative effects, Lumian trusted that Fourth Epoch Trier, with its potent seal isolating external influences, provided a safeguard. Even the boons of evil gods couldn't trace back to their source, making it unlikely for him to hear the Hidden Sage's ravings.
In this realm, there should be no adverse effects when using the Eye of Truth, especially within the mirror's Fourth Epoch Trier.
However, Lumian acknowledged the potential presence of a fallen Angel from the Mystery Pryer pathway or remnants of corresponding divine power. Even with the Eye of Truth, there was a chance of hearing voices he shouldn't. Consequently, Lumian didn't plan to use it extensively. He intended to locate Mirror Gardner Martin and remove the mystical item when the opportunity presented itself.