Professor: Yes,to establish or prove someone's criminal liability, we have to show by way of evidence and beyond reasonable doubt that he has committed a crime. This means two things must be proved. First, his outward conduct must amount to commission of a crime; and second, the state of his mind must be of a culpable nature. The legal term for requisite external is " actus reus," and the term for evil intent is "mens rea"
But intrinsically when you want to find out whether or not a person has mens rea, you will have to look at the conduct of the accused and draw an inference of what was on his mind. for evil conduct indicates the evil state of one's mind.
in this particular case, the internal act of firing at A is sufficient to satisfy the requirement of actus reus.