Now, if this was early Season 1, there would be reasons to wonder if perhaps Grace was snapping under all the emotional pressure.
Since this is early Season 2, the voice in her head can be taken as proof that Grace received a “calling” due to the fact that her child is Ben’s.
First, the good news!
When Ben and Grace decided they needed to find out the paternity of Grace’s baby as soon as possible rather than waiting months for the birth, the procedure took a turn for the weird when Grace heard a voice in her head telling her to stop the nurse from drawing blood.