Great!!! It bring me to my mind like a very well structured system for travelling in time, but after a while there is a road sign that tell that is not allowed to continue to navigate in time.
Of course, I think that is not the meaning inteded by you (I realized that later), but sometimes this misconceptions (as my knowledge of english is not perfect) are very inspirational. I remember to have read something similar, although it wasn't about time-machines (althought there were time-travelling) but about duplication machines. Fun read. I have to find it.
Anyway, back to the your point that I think I comprehend now better, you meant to paint this as a turning point, a decision stand, right?
You did a phenomenal work, I like it with its original meaning too.