Board Thread:General Discussion/@comment-7503158-20151003110949/@comment-24152851-20151003135817

We have to assume either both have no knowledge on each other, or both have knowledge. If the Doctor gets to stop the experiment, then Paradox gets to travel back to Gallifrey before the Doctor steals the TARDIS.

Besides, I don't think the Doctor would prevent Paradox from getting his powers, because if he did then the world would've ended a long time ago. As for the Chrono Navigator. I don't think Paradox is limited to it, it feels more like he created it to make time travel more convenient. He was the one who got thrown into the time vortex, not the fob watch.