Duh. The thing is, that you have to do things so fast, that you sometimes have to close cameras because there is someone at your door or else. You often don't have enough time too look at the cameras long enough (for RNG-based reasons)
You didn't mention any thing about it in your first comment so I was just making sure, no need to be rude just trying to help.
Also if you're still having trouble you can just leave both doors close and all you have to do is use the plush a lot more often, then you don't have to worry about Sammy, Poppi, Nile, and/or the shark girl killing you and you can focus on repairing, waiting on Nile's heart to fill up, and getting the gallery stuff in between using the plush.
That's how I beat it anyway.
P.S. None of this is to say the RNG is fair or good, the entire point of this strategy is to avoid most of the RNG issues.
Every character on that list (Sammy, Poppi, Nile, and the shark girl) is a character that you don't have to worry about if both doors are closed, that is what the list was about, why would I put Ari and the slomo girl in that list if both could still get you even if the doors are closed? Of course I didn't mention them in the comment about what you didn't need to worry about.
You need to worry about them!
P.S. I literally said in the first line of that strategy "all you have to do is use the plush a lot more often" if you are doing it enough Ari can't kill you and regarding the slomo girl, with most of the other girls unable to get to you with the doors closed you can spend more time on cams watching her which will keep her from getting to you.