Unreality Check

It is impossible to perceive a tear in the fabric of reality, because our minds cannot comprehend unreality. A tear in reality to our brains looks just like reality. The only difference is that if you walk into it, you not only cease to exist; you cease to ever have existed.

So was the fate of Doctor Jack Forrester, or it would have been if he ever had existed in this reality. (It becomes difficult to accurately describe such things when dealing with realities that no longer exist.) He had caused the rip, and so undid it as he undid himself.