Ok so this is unlikely to happen and is probably totally wrong but whatever, I thought I'd share it.
Orochimaru is taking Sasuke to his laboratory. Orochimaru has cells from the First Hokage who was a Senju, when Senju and Uchiha DNA is mixed it's possible to waken the Rinnegan as shown by Madara when he inserted the firsts DNA into himself. He needs the Rinnegan in order to fully read the tablets which were left by the Sage of the Six Paths, he can read some of the tablet with just his normal sharringan but he needs to the Rinnegan to fully decode it
Orochimaru is taking Sasuke to his laboratory. Orochimaru has cells from the First Hokage who was a Senju, when Senju and Uchiha DNA is mixed it's possible to waken the Rinnegan as shown by Madara when he inserted the firsts DNA into himself. He needs the Rinnegan in order to fully read the tablets which were left by the Sage of the Six Paths, he can read some of the tablet with just his normal sharringan but he needs to the Rinnegan to fully decode it