So here's my idea for how the time paradox AU would work; the human does 12 genocide runs in a row and then decides to try the pacifist route by resetting mid genocide, around the time of the hotland area, So before killing sans but after killing papyrus. the reset creates a glitch in the time space which allows the not yet killed genocide sans to enter the pacifist route timeline, then, he proceeds to tell pacifist sans what the human has done before and that they need to stop them before things get out of hand, together they convince papyrus not to capture the human and confront the human where papyrus usually would.