I'm not always right.
But Trump wants to win right now and if he has to clobber Carson, he won't hesitate. I suspected he would choose Carson to get more black voters, but he has a plethora of choices that can help him with the election.
The VP selection is usually used to shore you up with demographics/states where you are weak. He may choose a woman to even more effectively counter the Hillary "gender" mantra.
It's still early. Lots of people will be digging and dropping all sorts of bombs on the candidates of both parties.