As the Great Art of Destruction was executed, even Mo Wuji didn't wish to enter that area of destruction. In a space with many torn laws, who knew where he would be swept to once he entered it? It would still be fine if the Time Plate could locate his position. However, if the Time Plate couldn't do so, he would be wandering around the void for countless years.
Mo Wuji wouldn't mind wandering in the void for countless years if he was alone with no responsibility. This was because he could still cultivate anywhere he went. However, he had a pile of matters waiting on hand for him to handle. Even the Sage Tian Hen's calamity alone was enough reason for him not to leave God World.
With such an unreasonable Sage like Tian Hen around, exterminating a sect or even the entire God Domain shouldn't be a problem for him.
However, the Heaven Measuring Tree Root was simply too powerful. Even Mo Wuji couldn't control his urge to obtain it.
