"Of all men else I have avoided thee:
But get thee back, my soul is too much charg'd
With blood of thine already"
V, vii, 4-6.
MacBeth is realizing that MacDuff is about to fight him, and he knows that the witches said he would never be killed
by a man born of woman. Since he attained this knowledge, he does not care that MacDuff will be fighting him, since
he knows that he can not loose, and therefore, doesn't care how he speaks if it follows a pattern because he believes that
these will not be his final words.