My guess would be appeals. If he admits to the charges under oath it my ruin chances for appeals or open the door to further charges.
You're not paying legal attention, Arochi's lawyers have already set up the appeal. That's what asking the judge for admission of evidence, rulings on motions, objecting, and calling to testify is. They've been setting it up since the first witness took the stand.
Remember, on appeal, the court doesn't re-try the fact, they look to see whether the trial judge and jury applied and followed the law correctly.