It becomes more negative, slightly more negative. That is shown by phase one. So the movement of the positively charged ions out of the cell down their electrochemical gradient from a high concentration to a low concentration that causes the inside of the cell to basically become more negative. Now, this continues to take place until we reach about zero millivolts. When we reach about zero millivolts, the rate of movement of our sodium, of the potassium to the outside is equal to the rate of movement of the calcium inside. And what that basically means, because our rates are equal, because we have the positively charged potassium leaving the cell, but we have the positively charged calcium entering the cell, and the rates are equal.