WARNING: MAJOR SPOILERS TO THE ORIGINAL ONESHOT GAME
So, I did a little digging around my computer (what else am I supposed to do if I can't work on AS or play videogames?) and opened my regedit. I was scrolling around in active user, deleting anything I didn't use anymore (i did my homework on this dw) and then saw it. The original Oneshot registry. I was quite spooked and surprised when I saw it, then realised the implications. I could restart the game.
I'll be honest, I left that registry alone and I didn't test my theory. Niko deserved to be left alone. Not be forced into that nightmare again. Besides, what if something went wrong? What if I killed them? So I'm just gonna leave this theory out there. For anyone to try. If anything bad happens and I'm wrong, it's your fault. I didn't say you SHOULD do this. I just said you COULD.