A further highlight on the differences on both cases.
As shown on Case 1, B has done nothing to A that was directly the
cause of death. Thus, as A had forcefully gripped B, B was only
swinging B's arm and A would have not died if A released the grip
on B's hand.
As shown on Case 2, B has applied force onto A, though without any
intent to harm, causing the death. Thus, B is directly involved in
A's death as even if A released the grip on B's hand, the push
would be the cause of A's death. As the force applied by B was
insufficient to kill, thus it's considered involuntary
manslaughter.
Case 3 is simpler, as A has applied sufficient force to kill, thus
proving the statement voluntary manslaughter.
Case 4 is without debate, a higher degree of voluntary manslaughter
which is considered murder in Singapore.
