Merging

The best thing he could do now was merge Maha-Vairocana's Immobility Scripture into the Omniscient Mirror. 

Maha-Vairocana's Immobility Scripture and the Omniscient Mirror were similar in the sense that both of them required him to be absolutely still in his inner state and maintain a calm mindset in order to observe and deal with everything around him.

While the Omniscient Mirror could not defeat the Divine Light Body, it had many other wonderful functions of its own, so it was much more useful than Maha-Vairocana's Immobility Scripture.

Therefore, if he managed to integrate the Immobility Scripture into the Omniscient Mirror, it would take the Omniscient Mirror to the next level. 

If not, he would not be able to use Maha-Vairocana's Immobility Scripture while circulating the Omniscient Mirror. Likewise, when circulating Maha-Vairocana's Immobility Scripture, he would not be able to use the Omniscient Mirror. This would become a great inconvenience.