>>535985526
Because this is the second timeline, dumbo. Remember the train scene at the start of the game, GSC president bleeding out on the train, while she tells you how the current world was a failure because she thought she was smarter than she was but she failed, this time around she's going to trust sensei to handle things. Last timeline sensei and Arona were both there at the same time, but Arona chose to listen to herself instead of sensei, and she ended up with a bad ending in the end because of it, sensei kept trying to tell her but she thought she knew best, she says on the train that even if sensei doesn't remember the conversation they're having now, she trusts that he'll make the right choice next time without her there

She removed herself from the scenerio so she sensei could do things himself this time around, but at the same time she wanted to protect sensei. She rewound the world using the tablet, and at the same time she became the new AI from the tablet, most likely merging with A.R.O.N.A in the process.

In the new timeline before she disappeared she created Schale as basically a "Fuck you" level of authority that could override any other authority in Kivitos, so the GSC couldn't simply override sensei on everything like they did in the original timeline. Sensei needed complete authority in order to handle shit, or at least she thought he did.

The same choices, in the same situation
The world would all play out one more time, but this time arona trusted sensei could handle it without herself getting in the way.