Had Aksai left Varesh's body untouched for a few more seconds, the fail-safe method would have been activated.
It wouldn't have restored Varesh to his original condition completely, but it would have allowed him to recover from a mortal injury to a certain extent, saving his life.
However, Aksai had inflicted another mortal injury on the corpse.
The increased damage interfered with the fail-safe method's activation.
And before it could get another chance—
Aksai had already severed Varesh's connection with the outside world by storing his corpse inside the Enchanted Everwood Farm.
The Dao methods available only to Nascent Soul realm cultivators were bound to lose their effect once their carriers were sent into isolated dimensions that had somewhat incomplete elemental laws.
As such, the fail-safe method became useless.
Aksai knew none of this.
