Okay, look, I know I am late, but here's a strat to beat Factory without any kind of trouble.
First and foremost - Remember how Baby and Ballora act. The first makes two sounds as she moves, and if she moves third time, game over. Ballora moves to your location and you can hear her music getting louder, I recommend switching to the last cam on monitor and just keep track on her.
Now, the strat itself - while flashing light on Baby, she will not move at all. Flicking (quick camera turning) to monitor and then back on baby will prove efficient, as she will not have enough time to move. Once Ballora is close, you shut the door, and wait for sound cue, then, open it, and do your thing on tablet.
If Baby, ever, moves, use a controlled shock. You can spare her one or even two moves, just be careful and know your stuff, as restarting energy takes a while. It's best to get Ballora out of the way and stun baby, then, restart energy and do the task.
This strat can take some time, and practice is always needed, but I hope that mini guide helped you.