He's probably baiting hillary into assassinating him.
That's probably what he means by ruin her career.
who in their right mind would bait someone to murder them
It's more than likely he's afraid if he releases it too early it will do nothing, and he knows that it will only mean his death.
If he doesn't remind people of the information existence because if he doesn't he almost certainly will end up """"""""""committing Self Delete""""""""""
atleast if he alerts everyone, the public eye is on him and if he somehow ends up dead, everyone will have an even more sharp eye on Hillary.
In other words, Unfortunately, this mans death is inevitable, he is waiting for the right time to spring his trap, and hes trying not to get himself killed early in the process.